diff --git a/superset-frontend/cypress-base/cypress/integration/dashboard/dashboard.helper.ts b/superset-frontend/cypress-base/cypress/integration/dashboard/dashboard.helper.ts
new file mode 100644
index 0000000000000..10a42b7a194a4
--- /dev/null
+++ b/superset-frontend/cypress-base/cypress/integration/dashboard/dashboard.helper.ts
@@ -0,0 +1,47 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+export const WORLD_HEALTH_DASHBOARD = '/superset/dashboard/world_health/';
+export const TABBED_DASHBOARD = '/superset/dashboard/tabbed_dash/';
+
+export const CHECK_DASHBOARD_FAVORITE_ENDPOINT =
+  '/superset/favstar/Dashboard/*/count';
+
+/**
+ * Drag an element and drop it to another element.
+ * Usage:
+ *    drag(source).to(target);
+ */
+export function drag(selector: string, content: string | number | RegExp) {
+  const dataTransfer = { data: {} };
+  return {
+    to(target: string | Cypress.Chainable) {
+      cy.get('.dragdroppable')
+        .contains(selector, content)
+        .trigger('mousedown', { which: 1 })
+        .trigger('dragstart', { dataTransfer })
+        .trigger('drag', {});
+
+      (typeof target === 'string' ? cy.get(target) : target)
+        .trigger('dragover', { dataTransfer })
+        .trigger('drop', { dataTransfer })
+        .trigger('dragend', { dataTransfer })
+        .trigger('mouseup', { which: 1 });
+    },
+  };
+}
diff --git a/superset-frontend/cypress-base/cypress/integration/dashboard/edit_mode.test.js b/superset-frontend/cypress-base/cypress/integration/dashboard/edit_mode.test.js
index 1db86b5cda794..6202eb9f853e6 100644
--- a/superset-frontend/cypress-base/cypress/integration/dashboard/edit_mode.test.js
+++ b/superset-frontend/cypress-base/cypress/integration/dashboard/edit_mode.test.js
@@ -16,7 +16,7 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-import { WORLD_HEALTH_DASHBOARD } from './dashboard.helper';
+import { WORLD_HEALTH_DASHBOARD, drag } from './dashboard.helper';
 
 describe('Dashboard edit mode', () => {
   beforeEach(() => {
@@ -45,19 +45,9 @@ describe('Dashboard edit mode', () => {
       .find('.chart-card-container')
       .contains('Box plot');
 
-    // drag-n-drop
-    const dataTransfer = { data: {} };
-    cy.get('.dragdroppable')
-      .contains('Box plot')
-      .trigger('mousedown', { which: 1 })
-      .trigger('dragstart', { dataTransfer })
-      .trigger('drag', {});
-    cy.get('.grid-content div.grid-row.background--transparent')
-      .last()
-      .trigger('dragover', { dataTransfer })
-      .trigger('drop', { dataTransfer })
-      .trigger('dragend', { dataTransfer })
-      .trigger('mouseup', { which: 1 });
+    drag('.chart-card', 'Box plot').to(
+      '.grid-row.background--transparent:last',
+    );
 
     // add back to dashboard
     cy.get('.grid-container .box_plot').should('be.exist');
diff --git a/superset-frontend/cypress-base/cypress/integration/dashboard/markdown.test.ts b/superset-frontend/cypress-base/cypress/integration/dashboard/markdown.test.ts
new file mode 100644
index 0000000000000..a5f470fa52dd4
--- /dev/null
+++ b/superset-frontend/cypress-base/cypress/integration/dashboard/markdown.test.ts
@@ -0,0 +1,64 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import { TABBED_DASHBOARD, drag } from './dashboard.helper';
+
+describe('Dashboard edit markdown', () => {
+  beforeEach(() => {
+    cy.server();
+    cy.login();
+    cy.visit(TABBED_DASHBOARD);
+  });
+
+  it('should load AceEditor on demand', () => {
+    let numScripts = 0;
+    cy.get('script').then(nodes => {
+      numScripts = nodes.length;
+    });
+    cy.get('.dashboard-header [data-test=pencil]').click();
+    cy.get('script').then(nodes => {
+      // load 5 new script chunks for css editor
+      expect(nodes.length).to.greaterThan(numScripts);
+      numScripts = nodes.length;
+    });
+
+    // add new markdown component
+    drag('.new-component', 'Markdown').to(
+      '.grid-row.background--transparent:first',
+    );
+    cy.get('script').then(nodes => {
+      // load more scripts for markdown editor
+      expect(nodes.length).to.greaterThan(numScripts);
+      numScripts = nodes.length;
+    });
+
+    cy.contains('h3', '✨Markdown').click();
+    cy.get('.ace_content').contains(
+      'Click here to edit [markdown](https://bit.ly/1dQOfRK)',
+    );
+
+    // entering edit mode does not add new scripts
+    // (though scripts may still be removed by others)
+    cy.get('script').then(nodes => {
+      expect(nodes.length).to.most(numScripts);
+    });
+
+    cy.get('.grid-row.background--transparent:first').click('right');
+    cy.get('.ace_content').should('not.exist');
+  });
+});
diff --git a/superset-frontend/cypress-base/cypress/integration/explore/AdhocFilters.test.ts b/superset-frontend/cypress-base/cypress/integration/explore/AdhocFilters.test.ts
index c51da29acd849..d1969f341d862 100644
--- a/superset-frontend/cypress-base/cypress/integration/explore/AdhocFilters.test.ts
+++ b/superset-frontend/cypress-base/cypress/integration/explore/AdhocFilters.test.ts
@@ -25,14 +25,31 @@ describe('AdhocFilters', () => {
     cy.route('GET', '/superset/filter/table/*/name').as('filterValues');
   });
 
-  it('Set simple adhoc filter', () => {
-    cy.visitChartByName('Num Births Trend');
+  it('Should not load mathjs when not needed', () => {
+    cy.visitChartByName('Boys'); // a table chart
     cy.verifySliceSuccess({ waitAlias: '@postJson' });
+    cy.get('script[src*="mathjs"]').should('have.length', 0);
+  });
+
+  let numScripts = 0;
+
+  it('Should load AceEditor scripts when needed', () => {
+    cy.get('script').then(nodes => {
+      numScripts = nodes.length;
+    });
 
     cy.get('[data-test=adhoc_filters]').within(() => {
-      cy.get('.Select__control').click();
+      cy.get('.Select__control').scrollIntoView().click();
       cy.get('input[type=text]').focus().type('name{enter}');
     });
+
+    cy.get('script').then(nodes => {
+      // should load new script chunks for SQL editor
+      expect(nodes.length).to.greaterThan(numScripts);
+    });
+  });
+
+  it('Set simple adhoc filter', () => {
     cy.get('#filter-edit-popover').within(() => {
       cy.get('[data-test=adhoc-filter-simple-value]').within(() => {
         cy.get('.Select__control').click();
@@ -40,7 +57,6 @@ describe('AdhocFilters', () => {
       });
       cy.get('button').contains('Save').click();
     });
-
     cy.get('button[data-test="run-query-button"]').click();
     cy.verifySliceSuccess({
       waitAlias: '@postJson',
@@ -52,19 +68,21 @@ describe('AdhocFilters', () => {
     cy.visitChartByName('Num Births Trend');
     cy.verifySliceSuccess({ waitAlias: '@postJson' });
 
-    cy.get('[data-test=adhoc_filters]').within(() => {
-      cy.get('.Select__control').click();
-      cy.get('input[type=text]').focus().type('name{enter}');
-    });
+    cy.get('[data-test=adhoc_filters] .Select__control')
+      .scrollIntoView()
+      .click();
+    cy.get('[data-test=adhoc_filters] input[type=text]')
+      .focus()
+      .type('name{enter}');
 
     cy.wait('@filterValues');
 
-    cy.get('#filter-edit-popover').within(() => {
-      cy.get('#adhoc-filter-edit-tabs-tab-SQL').click();
-      cy.get('.ace_content').click();
-      cy.get('.ace_text-input').type("'Amy' OR name = 'Bob'");
-      cy.get('button').contains('Save').click();
-    });
+    cy.get('#filter-edit-popover #adhoc-filter-edit-tabs-tab-SQL').click();
+    cy.get('#filter-edit-popover .ace_content').click();
+    cy.get('#filter-edit-popover .ace_text-input').type(
+      "'Amy' OR name = 'Bob'",
+    );
+    cy.get('#filter-edit-popover button').contains('Save').click();
 
     cy.get('button[data-test="run-query-button"]').click();
     cy.verifySliceSuccess({
diff --git a/superset-frontend/cypress-base/cypress/integration/explore/control.test.ts b/superset-frontend/cypress-base/cypress/integration/explore/control.test.ts
index 7a08611497354..647b31f7065b9 100644
--- a/superset-frontend/cypress-base/cypress/integration/explore/control.test.ts
+++ b/superset-frontend/cypress-base/cypress/integration/explore/control.test.ts
@@ -32,12 +32,25 @@ describe('Datasource control', () => {
   });
 
   it('should allow edit datasource', () => {
+    let numScripts = 0;
+
     cy.visitChartByName('Num Births Trend');
     cy.verifySliceSuccess({ waitAlias: '@postJson' });
     cy.get('#datasource_menu').click();
+
+    cy.get('script').then(nodes => {
+      numScripts = nodes.length;
+    });
+
     cy.get('a').contains('Edit Datasource').click();
+
+    // should load additional scripts for the modal
+    cy.get('script').then(nodes => {
+      expect(nodes.length).to.greaterThan(numScripts);
+    });
+
     // create new metric
-    cy.get('button').contains('Add Item').click();
+    cy.get('table button').contains('Add Item', { timeout: 10000 }).click();
     cy.get('input[value="<new metric>"]').click();
     cy.get('input[value="<new metric>"]')
       .focus()
@@ -65,19 +78,33 @@ describe('Datasource control', () => {
   });
 });
 
-describe('Groupby control', () => {
-  it('Set groupby', () => {
-    cy.server();
+describe('VizType control', () => {
+  beforeEach(() => {
     cy.login();
+    cy.server();
     cy.route('GET', '/superset/explore_json/**').as('getJson');
     cy.route('POST', '/superset/explore_json/**').as('postJson');
-    cy.visitChartByName('Num Births Trend');
+  });
+
+  it('Can change vizType', () => {
+    cy.visitChartByName('Daily Totals');
     cy.verifySliceSuccess({ waitAlias: '@postJson' });
 
-    cy.get('[data-test=groupby]').within(() => {
-      cy.get('.Select__control').click();
-      cy.get('input[type=text]').type('state{enter}');
+    let numScripts = 0;
+    cy.get('script').then(nodes => {
+      numScripts = nodes.length;
     });
+
+    cy.get('.Control .label').contains('Table').click();
+
+    cy.get('[role="button"]').contains('Line Chart').click();
+
+    // should load mathjs for line chart
+    cy.get('script[src*="mathjs"]').should('have.length', 1);
+    cy.get('script').then(nodes => {
+      expect(nodes.length).to.greaterThan(numScripts);
+    });
+
     cy.get('button[data-test="run-query-button"]').click();
     cy.verifySliceSuccess({ waitAlias: '@postJson', chartSelector: 'svg' });
   });
@@ -118,3 +145,21 @@ describe('Time range filter', () => {
     cy.get('#filter-popover').should('not.exist');
   });
 });
+
+describe('Groupby control', () => {
+  it('Set groupby', () => {
+    cy.server();
+    cy.login();
+    cy.route('GET', '/superset/explore_json/**').as('getJson');
+    cy.route('POST', '/superset/explore_json/**').as('postJson');
+    cy.visitChartByName('Num Births Trend');
+    cy.verifySliceSuccess({ waitAlias: '@postJson' });
+
+    cy.get('[data-test=groupby]').within(() => {
+      cy.get('.Select__control').click();
+      cy.get('input[type=text]').type('state{enter}');
+    });
+    cy.get('button[data-test="run-query-button"]').click();
+    cy.verifySliceSuccess({ waitAlias: '@postJson', chartSelector: 'svg' });
+  });
+});
diff --git a/superset-frontend/cypress-base/cypress/integration/explore/visualizations/line.test.ts b/superset-frontend/cypress-base/cypress/integration/explore/visualizations/line.test.ts
index 34f80f2b4916f..9467c71f5a4e0 100644
--- a/superset-frontend/cypress-base/cypress/integration/explore/visualizations/line.test.ts
+++ b/superset-frontend/cypress-base/cypress/integration/explore/visualizations/line.test.ts
@@ -33,6 +33,14 @@ describe('Visualization > Line', () => {
     cy.get('.alert-warning').contains(`"Metrics" cannot be empty`);
   });
 
+  it('should preload mathjs', () => {
+    cy.get('script[src*="mathjs"]').should('have.length', 1);
+    cy.contains('Add Annotation Layer').scrollIntoView().click();
+    // should not load additional mathjs
+    cy.get('script[src*="mathjs"]').should('have.length', 1);
+    cy.contains('Layer Configuration');
+  });
+
   it('should not show validator error when metric added', () => {
     const formData = { ...LINE_CHART_DEFAULTS, metrics: [] };
     cy.visitChartByParams(JSON.stringify(formData));
@@ -68,6 +76,7 @@ describe('Visualization > Line', () => {
     const formData = { ...LINE_CHART_DEFAULTS, metrics: [NUM_METRIC] };
     cy.visitChartByParams(JSON.stringify(formData));
     cy.verifySliceSuccess({ waitAlias: '@getJson', chartSelector: 'svg' });
+    cy.get('script[src*="mathjs"]').should('have.length', 1);
   });
 
   it('should work with groupby', () => {
diff --git a/superset-frontend/spec/javascripts/dashboard/components/gridComponents/Markdown_spec.jsx b/superset-frontend/spec/javascripts/dashboard/components/gridComponents/Markdown_spec.jsx
index e73c48f68372e..ad82b52f82c9a 100644
--- a/superset-frontend/spec/javascripts/dashboard/components/gridComponents/Markdown_spec.jsx
+++ b/superset-frontend/spec/javascripts/dashboard/components/gridComponents/Markdown_spec.jsx
@@ -20,9 +20,9 @@ import { Provider } from 'react-redux';
 import React from 'react';
 import { mount } from 'enzyme';
 import sinon from 'sinon';
-import AceEditor from 'react-ace';
 import ReactMarkdown from 'react-markdown';
 
+import { MarkdownEditor } from 'src/components/AsyncAceEditor';
 import Markdown from 'src/dashboard/components/gridComponents/Markdown';
 import MarkdownModeDropdown from 'src/dashboard/components/menu/MarkdownModeDropdown';
 import DeleteComponentButton from 'src/dashboard/components/DeleteComponentButton';
@@ -105,23 +105,23 @@ describe('Markdown', () => {
 
   it('should render an Markdown when NOT focused', () => {
     const wrapper = setup();
-    expect(wrapper.find(AceEditor)).not.toExist();
+    expect(wrapper.find(MarkdownEditor)).not.toExist();
     expect(wrapper.find(ReactMarkdown)).toExist();
   });
 
   it('should render an AceEditor when focused and editMode=true and editorMode=edit', () => {
     const wrapper = setup({ editMode: true });
-    expect(wrapper.find(AceEditor)).not.toExist();
+    expect(wrapper.find(MarkdownEditor)).not.toExist();
     expect(wrapper.find(ReactMarkdown)).toExist();
     wrapper.find(WithPopoverMenu).simulate('click'); // focus + edit
-    expect(wrapper.find(AceEditor)).toExist();
+    expect(wrapper.find(MarkdownEditor)).toExist();
     expect(wrapper.find(ReactMarkdown)).not.toExist();
   });
 
   it('should render a ReactMarkdown when focused and editMode=true and editorMode=preview', () => {
     const wrapper = setup({ editMode: true });
     wrapper.find(WithPopoverMenu).simulate('click'); // focus + edit
-    expect(wrapper.find(AceEditor)).toExist();
+    expect(wrapper.find(MarkdownEditor)).toExist();
     expect(wrapper.find(ReactMarkdown)).not.toExist();
 
     // we can't call setState on Markdown bc it's not the root component, so call
@@ -131,7 +131,7 @@ describe('Markdown', () => {
     wrapper.update();
 
     expect(wrapper.find(ReactMarkdown)).toExist();
-    expect(wrapper.find(AceEditor)).not.toExist();
+    expect(wrapper.find(MarkdownEditor)).not.toExist();
   });
 
   it('should call updateComponents when editMode changes from edit => preview, and there are markdownSource changes', () => {
@@ -148,7 +148,7 @@ describe('Markdown', () => {
     dropdown.prop('onChange')('edit');
     // because we can't call setState on Markdown, change it through the editor
     // then go back to preview mode to invoke updateComponents
-    const editor = wrapper.find(AceEditor);
+    const editor = wrapper.find(MarkdownEditor);
     editor.prop('onChange')('new markdown!');
     dropdown.prop('onChange')('preview');
     expect(updateComponents.callCount).toBe(1);
diff --git a/superset-frontend/spec/javascripts/explore/components/TextArea_spec.jsx b/superset-frontend/spec/javascripts/explore/components/TextArea_spec.jsx
index 4c656b5e1af74..57c34b24559f2 100644
--- a/superset-frontend/spec/javascripts/explore/components/TextArea_spec.jsx
+++ b/superset-frontend/spec/javascripts/explore/components/TextArea_spec.jsx
@@ -21,7 +21,7 @@ import React from 'react';
 import { FormControl } from 'react-bootstrap';
 import sinon from 'sinon';
 import { shallow } from 'enzyme';
-import AceEditor from 'react-ace';
+import { TextAreaEditor } from 'src/components/AsyncAceEditor';
 
 import TextAreaControl from 'src/explore/components/controls/TextAreaControl';
 
@@ -52,6 +52,6 @@ describe('SelectControl', () => {
     props.language = 'markdown';
     wrapper = shallow(<TextAreaControl {...props} />);
     expect(wrapper.find(FormControl)).not.toExist();
-    expect(wrapper.find(AceEditor)).toExist();
+    expect(wrapper.find(TextAreaEditor)).toExist();
   });
 });
diff --git a/superset-frontend/src/CRUD/CollectionTable.tsx b/superset-frontend/src/CRUD/CollectionTable.tsx
index 661547fbe55f5..f1620f43e9563 100644
--- a/superset-frontend/src/CRUD/CollectionTable.tsx
+++ b/superset-frontend/src/CRUD/CollectionTable.tsx
@@ -175,10 +175,10 @@ export default class CRUDCollection extends React.PureComponent<
           ))}
           {extraButtons}
           {allowDeletes && !allowAddItem && (
-            <th aria-label="Delete" className="tiny-cell" />
+            <th key="delete-item" aria-label="Delete" className="tiny-cell" />
           )}
           {allowAddItem && (
-            <th>
+            <th key="add-item">
               <Button buttonStyle="primary" onClick={this.onAddItem}>
                 <i className="fa fa-plus" /> {t('Add Item')}
               </Button>
@@ -237,7 +237,7 @@ export default class CRUDCollection extends React.PureComponent<
       )),
     );
     if (allowAddItem) {
-      tds.push(<td />);
+      tds.push(<td key="add" />);
     }
     if (allowDeletes) {
       tds.push(
diff --git a/superset-frontend/src/SqlLab/components/AceEditorWrapper.tsx b/superset-frontend/src/SqlLab/components/AceEditorWrapper.tsx
index a05ef3cdfae77..95c6eb8cfcfb1 100644
--- a/superset-frontend/src/SqlLab/components/AceEditorWrapper.tsx
+++ b/superset-frontend/src/SqlLab/components/AceEditorWrapper.tsx
@@ -17,11 +17,6 @@
  * under the License.
  */
 import React from 'react';
-import AceEditor from 'react-ace';
-import 'brace/mode/sql';
-import 'brace/theme/github';
-import 'brace/ext/language_tools';
-import ace from 'brace';
 import { areArraysShallowEqual } from 'src/reduxUtils';
 import sqlKeywords from 'src/SqlLab/utils/sqlKeywords';
 import {
@@ -30,8 +25,11 @@ import {
   COLUMN_AUTOCOMPLETE_SCORE,
   SQL_FUNCTIONS_AUTOCOMPLETE_SCORE,
 } from 'src/SqlLab/constants';
-
-const langTools = ace.acequire('ace/ext/language_tools');
+import {
+  Editor,
+  AceCompleterKeyword,
+  FullSQLEditor as AceEditor,
+} from 'src/components/AsyncAceEditor';
 
 type HotKey = {
   key: string;
@@ -61,7 +59,7 @@ interface Props {
 interface State {
   sql: string;
   selectedText: string;
-  words: any[];
+  words: AceCompleterKeyword[];
 }
 
 class AceEditorWrapper extends React.PureComponent<Props, State> {
@@ -151,43 +149,6 @@ class AceEditorWrapper extends React.PureComponent<Props, State> {
     this.props.onChange(text);
   }
 
-  getCompletions(
-    aceEditor: any,
-    session: any,
-    pos: any,
-    prefix: string,
-    callback: (p0: any, p1: any[]) => void,
-  ) {
-    // If the prefix starts with a number, don't try to autocomplete with a
-    // table name or schema or anything else
-    if (!Number.isNaN(parseInt(prefix, 10))) {
-      return;
-    }
-    const completer = {
-      insertMatch: (editor: any, data: any) => {
-        if (data.meta === 'table') {
-          this.props.actions.addTable(
-            this.props.queryEditor,
-            data.value,
-            this.props.queryEditor.schema,
-          );
-        }
-        editor.completer.insertMatch({
-          value: `${data.caption}${
-            ['function', 'schema'].includes(data.meta) ? '' : ' '
-          }`,
-        });
-      },
-    };
-    // Mutate instead of object spread here for performance
-    const words = this.state.words.map(word => {
-      /* eslint-disable-next-line no-param-reassign */
-      word.completer = completer;
-      return word;
-    });
-    callback(null, words);
-  }
-
   setAutoCompleter(props: Props) {
     // Loading schema, table and column names as auto-completable words
     const schemas = props.schemas || [];
@@ -229,20 +190,35 @@ class AceEditorWrapper extends React.PureComponent<Props, State> {
       meta: 'function',
     }));
 
+    const completer = {
+      insertMatch: (editor: Editor, data: any) => {
+        if (data.meta === 'table') {
+          this.props.actions.addTable(
+            this.props.queryEditor,
+            data.value,
+            this.props.queryEditor.schema,
+          );
+        }
+        // executing https://github.com/thlorenz/brace/blob/3a00c5d59777f9d826841178e1eb36694177f5e6/ext/language_tools.js#L1448
+        editor.completer.insertMatch(
+          `${data.caption}${
+            ['function', 'schema'].includes(data.meta) ? '' : ' '
+          }`,
+        );
+      },
+    };
+
     const words = schemaWords
       .concat(tableWords)
       .concat(columnWords)
       .concat(functionWords)
-      .concat(sqlKeywords);
+      .concat(sqlKeywords)
+      .map(word => ({
+        ...word,
+        completer,
+      }));
 
-    this.setState({ words }, () => {
-      const completer = {
-        getCompletions: this.getCompletions.bind(this),
-      };
-      if (langTools) {
-        langTools.setCompleters([completer]);
-      }
-    });
+    this.setState({ words });
   }
 
   getAceAnnotations() {
@@ -263,8 +239,7 @@ class AceEditorWrapper extends React.PureComponent<Props, State> {
   render() {
     return (
       <AceEditor
-        mode="sql"
-        theme="github"
+        keywords={this.state.words}
         onLoad={this.onEditorLoad.bind(this)}
         onBlur={this.onBlur.bind(this)}
         height={this.props.height}
diff --git a/superset-frontend/src/SqlLab/components/TemplateParamsEditor.jsx b/superset-frontend/src/SqlLab/components/TemplateParamsEditor.jsx
index 75b317fe5f743..a15f5638b514d 100644
--- a/superset-frontend/src/SqlLab/components/TemplateParamsEditor.jsx
+++ b/superset-frontend/src/SqlLab/components/TemplateParamsEditor.jsx
@@ -19,18 +19,12 @@
 import React from 'react';
 import PropTypes from 'prop-types';
 import { Badge } from 'react-bootstrap';
-import AceEditor from 'react-ace';
-import 'brace/mode/sql';
-import 'brace/mode/json';
-import 'brace/mode/html';
-import 'brace/mode/markdown';
-import 'brace/theme/textmate';
-
 import { t } from '@superset-ui/core';
 import { InfoTooltipWithTrigger } from '@superset-ui/chart-controls';
 
 import Button from 'src/components/Button';
-import ModalTrigger from '../../components/ModalTrigger';
+import ModalTrigger from 'src/components/ModalTrigger';
+import { ConfigEditor } from 'src/components/AsyncAceEditor';
 
 const propTypes = {
   onChange: PropTypes.func,
@@ -104,9 +98,9 @@ export default class TemplateParamsEditor extends React.Component {
     return (
       <div>
         {this.renderDoc()}
-        <AceEditor
+        <ConfigEditor
+          keywords={[]}
           mode={this.props.language}
-          theme="textmate"
           style={{ border: '1px solid #CCC' }}
           minLines={25}
           maxLines={50}
diff --git a/superset-frontend/src/components/AsyncAceEditor.tsx b/superset-frontend/src/components/AsyncAceEditor.tsx
new file mode 100644
index 0000000000000..0d394d9f3d492
--- /dev/null
+++ b/superset-frontend/src/components/AsyncAceEditor.tsx
@@ -0,0 +1,215 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import React from 'react';
+import {
+  Editor as OrigEditor,
+  IEditSession,
+  Position,
+  TextMode as OrigTextMode,
+} from 'brace';
+import AceEditor, { AceEditorProps } from 'react-ace';
+import AsyncEsmComponent, {
+  PlaceholderProps,
+} from 'src/components/AsyncEsmComponent';
+
+export interface AceCompleterKeywordData {
+  name: string;
+  value: string;
+  score: number;
+  meta: string;
+}
+
+export type TextMode = OrigTextMode & { $id: string };
+
+export interface AceCompleter {
+  insertMatch: (
+    data?: Editor | { value: string } | string,
+    options?: AceCompleterKeywordData,
+  ) => void;
+}
+
+export type Editor = OrigEditor & {
+  completer: AceCompleter;
+  completers: AceCompleter[];
+};
+
+export interface AceCompleterKeyword extends AceCompleterKeywordData {
+  completer?: AceCompleter;
+}
+
+/**
+ * Async loaders to import brace modules. Must manually create call `import(...)`
+ * promises because webpack can only analyze asycn imports statically.
+ */
+const aceModuleLoaders = {
+  'mode/sql': () => import('brace/mode/sql'),
+  'mode/markdown': () => import('brace/mode/markdown'),
+  'mode/css': () => import('brace/mode/css'),
+  'mode/json': () => import('brace/mode/json'),
+  'mode/yaml': () => import('brace/mode/yaml'),
+  'mode/html': () => import('brace/mode/html'),
+  'mode/javascript': () => import('brace/mode/javascript'),
+  'theme/textmate': () => import('brace/theme/textmate'),
+  'theme/github': () => import('brace/theme/github'),
+  'ext/language_tools': () => import('brace/ext/language_tools'),
+};
+
+export type AceModule = keyof typeof aceModuleLoaders;
+
+export type AsyncAceEditorProps = AceEditorProps & {
+  keywords?: AceCompleterKeyword[];
+};
+
+export type AceEditorMode = 'sql';
+export type AceEditorTheme = 'textmate' | 'github';
+export type AsyncAceEditorOptions = {
+  defaultMode?: AceEditorMode;
+  defaultTheme?: AceEditorTheme;
+  defaultTabSize?: number;
+  placeholder?: React.ComponentType<
+    PlaceholderProps & Partial<AceEditorProps>
+  > | null;
+};
+
+/**
+ * Get an async AceEditor with automatical loading of specified ace modules.
+ */
+export default function AsyncAceEditor(
+  aceModules: AceModule[],
+  {
+    defaultMode,
+    defaultTheme,
+    defaultTabSize = 2,
+    placeholder,
+  }: AsyncAceEditorOptions = {},
+) {
+  return AsyncEsmComponent(async () => {
+    const { default: ace } = await import('brace');
+    const { default: ReactAceEditor } = await import('react-ace');
+
+    await Promise.all(aceModules.map(x => aceModuleLoaders[x]()));
+
+    const inferredMode =
+      defaultMode ||
+      aceModules.find(x => x.startsWith('mode/'))?.replace('mode/', '');
+    const inferredTheme =
+      defaultTheme ||
+      aceModules.find(x => x.startsWith('theme/'))?.replace('theme/', '');
+
+    return React.forwardRef<AceEditor, AsyncAceEditorProps>(
+      function ExtendedAceEditor(
+        {
+          keywords,
+          mode = inferredMode,
+          theme = inferredTheme,
+          tabSize = defaultTabSize,
+          ...props
+        },
+        ref,
+      ) {
+        if (keywords) {
+          const langTools = ace.acequire('ace/ext/language_tools');
+          const completer = {
+            getCompletions: (
+              editor: AceEditor,
+              session: IEditSession,
+              pos: Position,
+              prefix: string,
+              callback: (error: null, wordList: object[]) => void,
+            ) => {
+              // If the prefix starts with a number, don't try to autocomplete
+              if (!Number.isNaN(parseInt(prefix, 10))) {
+                return;
+              }
+              if ((session.getMode() as TextMode).$id === `ace/mode/${mode}`) {
+                callback(null, keywords);
+              }
+            },
+          };
+          langTools.setCompleters([completer]);
+        }
+        return (
+          <ReactAceEditor
+            ref={ref}
+            mode={mode}
+            theme={theme}
+            tabSize={tabSize}
+            {...props}
+          />
+        );
+      },
+    );
+  }, placeholder);
+}
+
+export const SQLEditor = AsyncAceEditor([
+  'mode/sql',
+  'theme/github',
+  'ext/language_tools',
+]);
+
+export const FullSQLEditor = AsyncAceEditor(
+  ['mode/sql', 'theme/github', 'ext/language_tools'],
+  {
+    // a custom placeholder in SQL lab for less jumpy re-renders
+    placeholder: () => {
+      const gutterBackground = '#e8e8e8'; // from ace-github theme
+      return (
+        <div
+          style={{
+            height: '100%',
+          }}
+        >
+          <div
+            style={{ width: 41, height: '100%', background: gutterBackground }}
+          />
+          {/* make it possible to resize the placeholder */}
+          <div className="ace_content" />
+        </div>
+      );
+    },
+  },
+);
+
+export const MarkdownEditor = AsyncAceEditor([
+  'mode/markdown',
+  'theme/textmate',
+]);
+
+export const TextAreaEditor = AsyncAceEditor([
+  'mode/markdown',
+  'mode/sql',
+  'mode/json',
+  'mode/html',
+  'mode/javascript',
+  'theme/textmate',
+]);
+
+export const CssEditor = AsyncAceEditor(['mode/css', 'theme/github']);
+
+export const JsonEditor = AsyncAceEditor(['mode/json', 'theme/github']);
+
+/**
+ * JSON or Yaml config editor.
+ */
+export const ConfigEditor = AsyncAceEditor([
+  'mode/json',
+  'mode/yaml',
+  'theme/github',
+]);
diff --git a/superset-frontend/src/components/AsyncEsmComponent.tsx b/superset-frontend/src/components/AsyncEsmComponent.tsx
new file mode 100644
index 0000000000000..a502926f31d22
--- /dev/null
+++ b/superset-frontend/src/components/AsyncEsmComponent.tsx
@@ -0,0 +1,132 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import React, { CSSProperties, useEffect, useState, RefObject } from 'react';
+import Loading from './Loading';
+
+export type PlaceholderProps = {
+  showLoadingForImport?: boolean;
+  width?: string | number;
+  height?: string | number;
+  placeholderStyle?: CSSProperties;
+} & {
+  [key: string]: any;
+};
+
+function DefaultPlaceholder({
+  width,
+  height,
+  showLoadingForImport = false,
+  placeholderStyle: style,
+}: PlaceholderProps) {
+  return (
+    // since `width` defaults to 100%, we can display the placeholder once
+    // height is specified.
+    (height && (
+      <div key="async-asm-placeholder" style={{ width, height, ...style }}>
+        {showLoadingForImport && <Loading position="floating" />}
+      </div>
+    )) ||
+    // `|| null` is for in case of height=0.
+    null
+  );
+}
+
+/**
+ * Asynchronously import an ES module as a React component, render a placeholder
+ * first (if provided) and re-render once import is complete.
+ */
+export default function AsyncEsmComponent<
+  P = PlaceholderProps,
+  M = React.ComponentType<P> | { default: React.ComponentType<P> }
+>(
+  /**
+   * A promise generator that returns the React component to render.
+   */
+  loadComponent: Promise<M> | (() => Promise<M>),
+  /**
+   * Placeholder while still importing.
+   */
+  placeholder: React.ComponentType<
+    PlaceholderProps & Partial<P>
+  > | null = DefaultPlaceholder,
+) {
+  // component props + placeholder props
+  type FullProps = P & PlaceholderProps;
+  let promise: Promise<M> | undefined;
+  let component: React.ComponentType<FullProps>;
+
+  /**
+   * Safely wait for promise, make sure the loader function only execute once.
+   */
+  function waitForPromise() {
+    if (!promise) {
+      // load component on initialization
+      promise =
+        loadComponent instanceof Promise ? loadComponent : loadComponent();
+    }
+    if (!component) {
+      promise.then(result => {
+        component = ((result as { default?: React.ComponentType<P> }).default ||
+          result) as React.ComponentType<FullProps>;
+      });
+    }
+    return promise;
+  }
+
+  type AsyncComponent = React.ForwardRefExoticComponent<
+    React.PropsWithoutRef<FullProps> &
+      React.RefAttributes<React.ComponentType<FullProps>>
+  > & {
+    preload?: typeof waitForPromise;
+  };
+
+  const AsyncComponent: AsyncComponent = React.forwardRef(
+    function AsyncComponent(
+      props: FullProps,
+      ref: RefObject<React.ComponentType<FullProps>>,
+    ) {
+      const [loaded, setLoaded] = useState(component !== undefined);
+      useEffect(() => {
+        let isMounted = true;
+        if (!loaded) {
+          // update state to trigger a re-render
+          waitForPromise().then(() => {
+            if (isMounted) {
+              setLoaded(true);
+            }
+          });
+        }
+        return () => {
+          isMounted = false;
+        };
+      });
+      const Component = component || placeholder;
+      return Component ? (
+        // placeholder does not get the ref
+        <Component ref={Component === component ? ref : null} {...props} />
+      ) : null;
+    },
+  );
+  // preload the async component before rendering
+  AsyncComponent.preload = waitForPromise;
+
+  return AsyncComponent as AsyncComponent & {
+    preload: typeof waitForPromise;
+  };
+}
diff --git a/superset-frontend/src/dashboard/components/CssEditor.jsx b/superset-frontend/src/dashboard/components/CssEditor.jsx
index a412f6dfd6223..69f2500233d09 100644
--- a/superset-frontend/src/dashboard/components/CssEditor.jsx
+++ b/superset-frontend/src/dashboard/components/CssEditor.jsx
@@ -19,12 +19,9 @@
 import React from 'react';
 import PropTypes from 'prop-types';
 import Select from 'src/components/Select';
-import AceEditor from 'react-ace';
-import 'brace/mode/css';
-import 'brace/theme/github';
 import { t } from '@superset-ui/core';
-
-import ModalTrigger from '../../components/ModalTrigger';
+import ModalTrigger from 'src/components/ModalTrigger';
+import { CssEditor as AceCssEditor } from 'src/components/AsyncAceEditor';
 
 const propTypes = {
   initialCss: PropTypes.string,
@@ -49,6 +46,10 @@ class CssEditor extends React.PureComponent {
     this.changeCssTemplate = this.changeCssTemplate.bind(this);
   }
 
+  componentDidMount() {
+    AceCssEditor.preload();
+  }
+
   changeCss(css) {
     this.setState({ css }, () => {
       this.props.onChange(css);
@@ -87,10 +88,8 @@ class CssEditor extends React.PureComponent {
             <div style={{ zIndex: 1 }}>
               <h5>{t('Live CSS Editor')}</h5>
               <div style={{ border: 'solid 1px grey' }}>
-                <AceEditor
-                  mode="css"
-                  theme="github"
-                  minLines={8}
+                <AceCssEditor
+                  minLines={12}
                   maxLines={30}
                   onChange={this.changeCss}
                   height="200px"
diff --git a/superset-frontend/src/dashboard/components/Header.jsx b/superset-frontend/src/dashboard/components/Header.jsx
index 55ab3a82e5097..55f94aed938a3 100644
--- a/superset-frontend/src/dashboard/components/Header.jsx
+++ b/superset-frontend/src/dashboard/components/Header.jsx
@@ -23,14 +23,22 @@ import PropTypes from 'prop-types';
 import { styled, CategoricalColorNamespace, t } from '@superset-ui/core';
 import { ButtonGroup } from 'react-bootstrap';
 
+import {
+  LOG_ACTIONS_PERIODIC_RENDER_DASHBOARD,
+  LOG_ACTIONS_FORCE_REFRESH_DASHBOARD,
+  LOG_ACTIONS_TOGGLE_EDIT_DASHBOARD,
+} from 'src/logger/LogUtils';
+
 import Icon from 'src/components/Icon';
 import Button from 'src/components/Button';
+import EditableTitle from 'src/components/EditableTitle';
+import FaveStar from 'src/components/FaveStar';
+import { safeStringify } from 'src/utils/safeStringify';
 
 import HeaderActionsDropdown from './HeaderActionsDropdown';
-import EditableTitle from '../../components/EditableTitle';
-import FaveStar from '../../components/FaveStar';
 import PublishedStatus from './PublishedStatus';
 import UndoRedoKeylisteners from './UndoRedoKeylisteners';
+import PropertiesModal from './PropertiesModal';
 
 import { chartPropShape } from '../util/propShapes';
 import {
@@ -38,14 +46,6 @@ import {
   SAVE_TYPE_OVERWRITE,
   DASHBOARD_POSITION_DATA_LIMIT,
 } from '../util/constants';
-import { safeStringify } from '../../utils/safeStringify';
-
-import {
-  LOG_ACTIONS_PERIODIC_RENDER_DASHBOARD,
-  LOG_ACTIONS_FORCE_REFRESH_DASHBOARD,
-  LOG_ACTIONS_TOGGLE_EDIT_DASHBOARD,
-} from '../../logger/LogUtils';
-import PropertiesModal from './PropertiesModal';
 import setPeriodicRunner from '../util/setPeriodicRunner';
 import { options as PeriodicRefreshOptions } from './RefreshIntervalModal';
 
diff --git a/superset-frontend/src/dashboard/components/PropertiesModal.jsx b/superset-frontend/src/dashboard/components/PropertiesModal.jsx
index fe4ed2e7eac69..57f348282ee26 100644
--- a/superset-frontend/src/dashboard/components/PropertiesModal.jsx
+++ b/superset-frontend/src/dashboard/components/PropertiesModal.jsx
@@ -22,11 +22,12 @@ import { Row, Col, Modal, FormControl } from 'react-bootstrap';
 import Button from 'src/components/Button';
 import Dialog from 'react-bootstrap-dialog';
 import { AsyncSelect } from 'src/components/Select';
-import AceEditor from 'react-ace';
 import rison from 'rison';
 import { t, SupersetClient } from '@superset-ui/core';
 
 import FormLabel from 'src/components/FormLabel';
+import { JsonEditor } from 'src/components/AsyncAceEditor';
+
 import ColorSchemeControlWrapper from 'src/dashboard/components/ColorSchemeControlWrapper';
 import getClientErrorObject from '../../utils/getClientErrorObject';
 import withToasts from '../../messageToasts/enhancers/withToasts';
@@ -79,6 +80,7 @@ class PropertiesModal extends React.PureComponent {
 
   componentDidMount() {
     this.fetchDashboardDetails();
+    JsonEditor.preload();
   }
 
   onColorSchemeChange(value) {
@@ -304,13 +306,12 @@ class PropertiesModal extends React.PureComponent {
                     <FormLabel htmlFor="json_metadata">
                       {t('JSON Metadata')}
                     </FormLabel>
-                    <AceEditor
-                      mode="json"
+                    <JsonEditor
+                      showLoadingForImport
                       name="json_metadata"
                       defaultValue={this.defaultMetadataValue}
                       value={values.json_metadata}
                       onChange={this.onMetadataChange}
-                      theme="textmate"
                       tabSize={2}
                       width="100%"
                       height="200px"
diff --git a/superset-frontend/src/dashboard/components/gridComponents/Markdown.jsx b/superset-frontend/src/dashboard/components/gridComponents/Markdown.jsx
index 8da74f30e8f08..c5d86ceb817ab 100644
--- a/superset-frontend/src/dashboard/components/gridComponents/Markdown.jsx
+++ b/superset-frontend/src/dashboard/components/gridComponents/Markdown.jsx
@@ -20,10 +20,9 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import ReactMarkdown from 'react-markdown';
 import cx from 'classnames';
-import AceEditor from 'react-ace';
-import 'brace/mode/markdown';
-import 'brace/theme/textmate';
 import { t } from '@superset-ui/core';
+import { Logger, LOG_ACTIONS_RENDER_CHART } from 'src/logger/LogUtils';
+import { MarkdownEditor } from 'src/components/AsyncAceEditor';
 
 import DeleteComponentButton from '../DeleteComponentButton';
 import DragDroppable from '../dnd/DragDroppable';
@@ -37,7 +36,6 @@ import {
   GRID_MIN_ROW_UNITS,
   GRID_BASE_UNIT,
 } from '../../util/constants';
-import { Logger, LOG_ACTIONS_RENDER_CHART } from '../../../logger/LogUtils';
 
 const propTypes = {
   id: PropTypes.string.isRequired,
@@ -166,6 +164,10 @@ class Markdown extends React.PureComponent {
     ) {
       this.state.editor.resize(true);
     }
+    // pre-load AceEditor when entering edit mode
+    if (this.props.editMode) {
+      MarkdownEditor.preload();
+    }
   }
 
   componentDidCatch() {
@@ -230,9 +232,7 @@ class Markdown extends React.PureComponent {
 
   renderEditMode() {
     return (
-      <AceEditor
-        mode="markdown"
-        theme="textmate"
+      <MarkdownEditor
         onChange={this.handleMarkdownChange}
         width="100%"
         height="100%"
diff --git a/superset-frontend/src/datasource/DatasourceEditor.jsx b/superset-frontend/src/datasource/DatasourceEditor.jsx
index ce85ef725ec82..5efc4328097b0 100644
--- a/superset-frontend/src/datasource/DatasourceEditor.jsx
+++ b/superset-frontend/src/datasource/DatasourceEditor.jsx
@@ -27,20 +27,22 @@ import Button from 'src/components/Button';
 import Loading from 'src/components/Loading';
 import TableSelector from 'src/components/TableSelector';
 import CertifiedIconWithTooltip from 'src/components/CertifiedIconWithTooltip';
+import EditableTitle from 'src/components/EditableTitle';
 
-import getClientErrorObject from '../utils/getClientErrorObject';
-import CheckboxControl from '../explore/components/controls/CheckboxControl';
-import TextControl from '../explore/components/controls/TextControl';
-import SelectControl from '../explore/components/controls/SelectControl';
-import TextAreaControl from '../explore/components/controls/TextAreaControl';
-import SelectAsyncControl from '../explore/components/controls/SelectAsyncControl';
-import SpatialControl from '../explore/components/controls/SpatialControl';
-import CollectionTable from '../CRUD/CollectionTable';
-import EditableTitle from '../components/EditableTitle';
-import Fieldset from '../CRUD/Fieldset';
-import Field from '../CRUD/Field';
-
-import withToasts from '../messageToasts/enhancers/withToasts';
+import getClientErrorObject from 'src/utils/getClientErrorObject';
+
+import CheckboxControl from 'src/explore/components/controls/CheckboxControl';
+import TextControl from 'src/explore/components/controls/TextControl';
+import SelectControl from 'src/explore/components/controls/SelectControl';
+import TextAreaControl from 'src/explore/components/controls/TextAreaControl';
+import SelectAsyncControl from 'src/explore/components/controls/SelectAsyncControl';
+import SpatialControl from 'src/explore/components/controls/SpatialControl';
+
+import CollectionTable from 'src/CRUD/CollectionTable';
+import Fieldset from 'src/CRUD/Fieldset';
+import Field from 'src/CRUD/Field';
+
+import withToasts from 'src/messageToasts/enhancers/withToasts';
 
 const DatasourceContainer = styled.div`
   .tab-content {
diff --git a/superset-frontend/src/datasource/DatasourceModal.tsx b/superset-frontend/src/datasource/DatasourceModal.tsx
index 4f60028c4f842..9ff1de7f6b12d 100644
--- a/superset-frontend/src/datasource/DatasourceModal.tsx
+++ b/superset-frontend/src/datasource/DatasourceModal.tsx
@@ -22,10 +22,12 @@ import Button from 'src/components/Button';
 // @ts-ignore
 import Dialog from 'react-bootstrap-dialog';
 import { t, SupersetClient } from '@superset-ui/core';
+import AsyncEsmComponent from 'src/components/AsyncEsmComponent';
 
-import getClientErrorObject from '../utils/getClientErrorObject';
-import DatasourceEditor from './DatasourceEditor';
-import withToasts from '../messageToasts/enhancers/withToasts';
+import getClientErrorObject from 'src/utils/getClientErrorObject';
+import withToasts from 'src/messageToasts/enhancers/withToasts';
+
+const DatasourceEditor = AsyncEsmComponent(() => import('./DatasourceEditor'));
 
 interface DatasourceModalProps {
   addSuccessToast: (msg: string) => void;
@@ -150,6 +152,8 @@ const DatasourceModal: FunctionComponent<DatasourceModalProps> = ({
       <Modal.Body>
         {show && (
           <DatasourceEditor
+            showLoadingForImport
+            height={500}
             datasource={currentDatasource}
             onChange={onDatasourceChange}
           />
diff --git a/superset-frontend/src/explore/components/AdhocFilterEditPopoverSqlTabContent.jsx b/superset-frontend/src/explore/components/AdhocFilterEditPopoverSqlTabContent.jsx
index 49d616bd465bf..c8ea487422ec5 100644
--- a/superset-frontend/src/explore/components/AdhocFilterEditPopoverSqlTabContent.jsx
+++ b/superset-frontend/src/explore/components/AdhocFilterEditPopoverSqlTabContent.jsx
@@ -18,16 +18,12 @@
  */
 import React from 'react';
 import PropTypes from 'prop-types';
-import AceEditor from 'react-ace';
-import ace from 'brace';
-import 'brace/mode/sql';
-import 'brace/theme/github';
-import 'brace/ext/language_tools';
 import { FormGroup } from 'react-bootstrap';
 import Select from 'src/components/Select';
 import { t } from '@superset-ui/core';
+import { SQLEditor } from 'src/components/AsyncAceEditor';
+import sqlKeywords from 'src/SqlLab/utils/sqlKeywords';
 
-import sqlKeywords from '../../SqlLab/utils/sqlKeywords';
 import AdhocFilter, { EXPRESSION_TYPES, CLAUSES } from '../AdhocFilter';
 import adhocMetricType from '../propTypes/adhocMetricType';
 import columnType from '../propTypes/columnType';
@@ -45,8 +41,6 @@ const propTypes = {
   height: PropTypes.number.isRequired,
 };
 
-const langTools = ace.acequire('ace/ext/language_tools');
-
 export default class AdhocFilterEditPopoverSqlTabContent extends React.Component {
   constructor(props) {
     super(props);
@@ -63,32 +57,12 @@ export default class AdhocFilterEditPopoverSqlTabContent extends React.Component
       autosize: false,
       clearable: false,
     };
-
-    if (langTools) {
-      const words = sqlKeywords.concat(
-        this.props.options.map(option => {
-          if (option.column_name) {
-            return {
-              name: option.column_name,
-              value: option.column_name,
-              score: 50,
-              meta: 'option',
-            };
-          }
-          return null;
-        }),
-      );
-      const completer = {
-        getCompletions: (aceEditor, session, pos, prefix, callback) => {
-          callback(null, words);
-        },
-      };
-      langTools.setCompleters([completer]);
-    }
   }
 
   componentDidUpdate() {
-    this.aceEditorRef.editor.resize();
+    if (this.aceEditorRef) {
+      this.aceEditorRef.editor.resize();
+    }
   }
 
   onSqlExpressionClauseChange(clause) {
@@ -116,7 +90,7 @@ export default class AdhocFilterEditPopoverSqlTabContent extends React.Component
   }
 
   render() {
-    const { adhocFilter, height } = this.props;
+    const { adhocFilter, height, options } = this.props;
 
     const clauseSelectProps = {
       placeholder: t('choose WHERE or HAVING...'),
@@ -124,6 +98,21 @@ export default class AdhocFilterEditPopoverSqlTabContent extends React.Component
       value: adhocFilter.clause,
       onChange: this.onSqlExpressionClauseChange,
     };
+    const keywords = sqlKeywords.concat(
+      options
+        .map(option => {
+          if (option.column_name) {
+            return {
+              name: option.column_name,
+              value: option.column_name,
+              score: 50,
+              meta: 'option',
+            };
+          }
+          return null;
+        })
+        .filter(Boolean),
+    );
 
     return (
       <span>
@@ -140,10 +129,9 @@ export default class AdhocFilterEditPopoverSqlTabContent extends React.Component
           </span>
         </FormGroup>
         <FormGroup>
-          <AceEditor
+          <SQLEditor
             ref={this.handleAceEditorRef}
-            mode="sql"
-            theme="github"
+            keywords={keywords}
             height={`${height - 100}px`}
             onChange={this.onSqlExpressionChange}
             width="100%"
diff --git a/superset-frontend/src/explore/components/AdhocMetricEditPopover.jsx b/superset-frontend/src/explore/components/AdhocMetricEditPopover.jsx
index 192ad2364c6c9..1e49bc6a643cc 100644
--- a/superset-frontend/src/explore/components/AdhocMetricEditPopover.jsx
+++ b/superset-frontend/src/explore/components/AdhocMetricEditPopover.jsx
@@ -21,23 +21,17 @@ import PropTypes from 'prop-types';
 import { FormGroup, Popover, Tab, Tabs } from 'react-bootstrap';
 import Button from 'src/components/Button';
 import Select from 'src/components/Select';
-import ace from 'brace';
-import AceEditor from 'react-ace';
-import 'brace/mode/sql';
-import 'brace/theme/github';
-import 'brace/ext/language_tools';
 import { t, ThemeProvider } from '@superset-ui/core';
 import { ColumnOption } from '@superset-ui/chart-controls';
 
 import FormLabel from 'src/components/FormLabel';
+import { SQLEditor } from 'src/components/AsyncAceEditor';
+import sqlKeywords from 'src/SqlLab/utils/sqlKeywords';
 
 import { AGGREGATES_OPTIONS } from '../constants';
 import AdhocMetricEditPopoverTitle from './AdhocMetricEditPopoverTitle';
 import columnType from '../propTypes/columnType';
 import AdhocMetric, { EXPRESSION_TYPES } from '../AdhocMetric';
-import sqlKeywords from '../../SqlLab/utils/sqlKeywords';
-
-const langTools = ace.acequire('ace/ext/language_tools');
 
 const propTypes = {
   adhocMetric: PropTypes.instanceOf(AdhocMetric).isRequired,
@@ -80,22 +74,6 @@ export default class AdhocMetricEditPopover extends React.Component {
       autosize: false,
       clearable: true,
     };
-    if (langTools) {
-      const words = sqlKeywords.concat(
-        this.props.columns.map(column => ({
-          name: column.column_name,
-          value: column.column_name,
-          score: 50,
-          meta: 'column',
-        })),
-      );
-      const completer = {
-        getCompletions: (aceEditor, session, pos, prefix, callback) => {
-          callback(null, words);
-        },
-      };
-      langTools.setCompleters([completer]);
-    }
     document.addEventListener('mouseup', this.onMouseUp);
   }
 
@@ -179,7 +157,11 @@ export default class AdhocMetricEditPopover extends React.Component {
   }
 
   refreshAceEditor() {
-    setTimeout(() => this.aceEditorRef.editor.resize(), 0);
+    setTimeout(() => {
+      if (this.aceEditorRef) {
+        this.aceEditorRef.editor.resize();
+      }
+    }, 0);
   }
 
   renderColumnOption(option) {
@@ -199,6 +181,14 @@ export default class AdhocMetricEditPopover extends React.Component {
     } = this.props;
 
     const { adhocMetric } = this.state;
+    const keywords = sqlKeywords.concat(
+      columns.map(column => ({
+        name: column.column_name,
+        value: column.column_name,
+        score: 50,
+        meta: 'column',
+      })),
+    );
 
     const columnSelectProps = {
       placeholder: t('%s column(s)', columns.length),
@@ -279,10 +269,10 @@ export default class AdhocMetricEditPopover extends React.Component {
             >
               {this.props.datasourceType !== 'druid' ? (
                 <FormGroup>
-                  <AceEditor
+                  <SQLEditor
+                    showLoadingForImport
                     ref={this.handleAceEditorRef}
-                    mode="sql"
-                    theme="github"
+                    keywords={keywords}
                     height={`${this.state.height - 43}px`}
                     onChange={this.onSqlExpressionChange}
                     width="100%"
diff --git a/superset-frontend/src/explore/components/controls/AnnotationLayerControl.jsx b/superset-frontend/src/explore/components/controls/AnnotationLayerControl.jsx
index f6f49f204eae3..8980a2d8ad6a1 100644
--- a/superset-frontend/src/explore/components/controls/AnnotationLayerControl.jsx
+++ b/superset-frontend/src/explore/components/controls/AnnotationLayerControl.jsx
@@ -27,10 +27,15 @@ import {
 import { connect } from 'react-redux';
 import { t, withTheme } from '@superset-ui/core';
 import { InfoTooltipWithTrigger } from '@superset-ui/chart-controls';
-import { getChartKey } from '../../exploreUtils';
-import { runAnnotationQuery } from '../../../chart/chartAction';
+import AsyncEsmComponent from 'src/components/AsyncEsmComponent';
+import { getChartKey } from 'src/explore/exploreUtils';
+import { runAnnotationQuery } from 'src/chart/chartAction';
 
-import AnnotationLayer from './AnnotationLayer';
+const AnnotationLayer = AsyncEsmComponent(
+  () => import('./AnnotationLayer'),
+  // size of overlay inner content
+  () => <div style={{ width: 450, height: 368 }} />,
+);
 
 const propTypes = {
   colorScheme: PropTypes.string.isRequired,
@@ -61,6 +66,11 @@ class AnnotationLayerControl extends React.PureComponent {
     this.removeAnnotationLayer = this.removeAnnotationLayer.bind(this);
   }
 
+  componentDidMount() {
+    // preload the AnotationLayer component and dependent libraries i.e. mathjs
+    AnnotationLayer.preload();
+  }
+
   UNSAFE_componentWillReceiveProps(nextProps) {
     const { name, annotationError, validationErrors, value } = nextProps;
     if (Object.keys(annotationError).length && !validationErrors.length) {
@@ -111,6 +121,7 @@ class AnnotationLayerControl extends React.PureComponent {
       >
         <AnnotationLayer
           {...annotation}
+          parent={this.refs[parent]}
           error={error}
           colorScheme={this.props.colorScheme}
           vizType={this.props.vizType}
diff --git a/superset-frontend/src/explore/components/controls/DatasourceControl.jsx b/superset-frontend/src/explore/components/controls/DatasourceControl.jsx
index c06d493b7429a..04f3c031cfa80 100644
--- a/superset-frontend/src/explore/components/controls/DatasourceControl.jsx
+++ b/superset-frontend/src/explore/components/controls/DatasourceControl.jsx
@@ -32,10 +32,12 @@ import { t } from '@superset-ui/core';
 import { ColumnOption, MetricOption } from '@superset-ui/chart-controls';
 
 import Label from 'src/components/Label';
+import TooltipWrapper from 'src/components/TooltipWrapper';
+
+import DatasourceModal from 'src/datasource/DatasourceModal';
+import ChangeDatasourceModal from 'src/datasource/ChangeDatasourceModal';
+
 import ControlHeader from '../ControlHeader';
-import DatasourceModal from '../../../datasource/DatasourceModal';
-import ChangeDatasourceModal from '../../../datasource/ChangeDatasourceModal';
-import TooltipWrapper from '../../../components/TooltipWrapper';
 import './DatasourceControl.less';
 
 const propTypes = {
diff --git a/superset-frontend/src/explore/components/controls/SpatialControl.jsx b/superset-frontend/src/explore/components/controls/SpatialControl.jsx
index 9cbfa45c6f51b..9553200aab5bb 100644
--- a/superset-frontend/src/explore/components/controls/SpatialControl.jsx
+++ b/superset-frontend/src/explore/components/controls/SpatialControl.jsx
@@ -23,10 +23,10 @@ import Button from 'src/components/Button';
 import { t } from '@superset-ui/core';
 
 import Label from 'src/components/Label';
+import PopoverSection from 'src/components/PopoverSection';
+import Checkbox from 'src/components/Checkbox';
 import ControlHeader from '../ControlHeader';
 import SelectControl from './SelectControl';
-import PopoverSection from '../../../components/PopoverSection';
-import Checkbox from '../../../components/Checkbox';
 
 const spatialTypes = {
   latlong: 'latlong',
diff --git a/superset-frontend/src/explore/components/controls/TextAreaControl.jsx b/superset-frontend/src/explore/components/controls/TextAreaControl.jsx
index 6ce32f25a29e9..060fe8887d963 100644
--- a/superset-frontend/src/explore/components/controls/TextAreaControl.jsx
+++ b/superset-frontend/src/explore/components/controls/TextAreaControl.jsx
@@ -19,20 +19,14 @@
 import React from 'react';
 import PropTypes from 'prop-types';
 import { FormGroup, FormControl } from 'react-bootstrap';
-import Button from 'src/components/Button';
-
-import AceEditor from 'react-ace';
-import 'brace/mode/sql';
-import 'brace/mode/json';
-import 'brace/mode/html';
-import 'brace/mode/markdown';
-import 'brace/mode/javascript';
-import 'brace/theme/textmate';
-
+import { debounce } from 'lodash';
 import { t } from '@superset-ui/core';
 
+import Button from 'src/components/Button';
+import { TextAreaEditor } from 'src/components/AsyncAceEditor';
+import ModalTrigger from 'src/components/ModalTrigger';
+
 import ControlHeader from '../ControlHeader';
-import ModalTrigger from '../../../components/ModalTrigger';
 
 const propTypes = {
   name: PropTypes.string,
@@ -65,6 +59,12 @@ const defaultProps = {
 };
 
 export default class TextAreaControl extends React.Component {
+  constructor() {
+    super();
+    this.onAceChangeDebounce = debounce(value => {
+      this.onAceChange(value);
+    }, 300);
+  }
   onControlChange(event) {
     this.props.onChange(event.target.value);
   }
@@ -75,18 +75,18 @@ export default class TextAreaControl extends React.Component {
 
   renderEditor(inModal = false) {
     const value = this.props.value || '';
+    const minLines = inModal ? 40 : this.props.minLines || 12;
     if (this.props.language) {
       return (
-        <AceEditor
+        <TextAreaEditor
           mode={this.props.language}
-          theme="textmate"
           style={{ border: '1px solid #CCC' }}
-          minLines={inModal ? 40 : this.props.minLines}
+          minLines={minLines}
           maxLines={inModal ? 1000 : this.props.maxLines}
-          onChange={this.onAceChange.bind(this)}
+          onChange={this.onAceChangeDebounce}
           width="100%"
+          height={`${minLines}em`}
           editorProps={{ $blockScrolling: true }}
-          enableLiveAutocompletion
           value={value}
           readOnly={this.props.readOnly}
         />
diff --git a/superset-frontend/cypress-base/cypress/integration/dashboard/dashboard.helper.js b/superset-frontend/src/types/brace.d.ts
similarity index 68%
rename from superset-frontend/cypress-base/cypress/integration/dashboard/dashboard.helper.js
rename to superset-frontend/src/types/brace.d.ts
index 250eb5e15c0a2..70d9275e41d4f 100644
--- a/superset-frontend/cypress-base/cypress/integration/dashboard/dashboard.helper.js
+++ b/superset-frontend/src/types/brace.d.ts
@@ -16,8 +16,13 @@
  * specific language governing permissions and limitations
  * under the License.
  */
-export const WORLD_HEALTH_DASHBOARD = '/superset/dashboard/world_health/';
-export const TABBED_DASHBOARD = '/superset/dashboard/tabbed_dash/';
-
-export const CHECK_DASHBOARD_FAVORITE_ENDPOINT =
-  '/superset/favstar/Dashboard/*/count';
+declare module 'brace/mode/sql';
+declare module 'brace/mode/markdown';
+declare module 'brace/mode/json';
+declare module 'brace/mode/css';
+declare module 'brace/mode/html';
+declare module 'brace/mode/yaml';
+declare module 'brace/mode/javascript';
+declare module 'brace/theme/textmate';
+declare module 'brace/theme/github';
+declare module 'brace/ext/language_tools';
diff --git a/superset-frontend/src/visualizations/FilterBox/FilterBox.jsx b/superset-frontend/src/visualizations/FilterBox/FilterBox.jsx
index 51dfc417c1cc4..311b7171999c7 100644
--- a/superset-frontend/src/visualizations/FilterBox/FilterBox.jsx
+++ b/superset-frontend/src/visualizations/FilterBox/FilterBox.jsx
@@ -26,20 +26,20 @@ import { t, styled, SupersetClient } from '@superset-ui/core';
 
 import FormLabel from 'src/components/FormLabel';
 
-import DateFilterControl from '../../explore/components/controls/DateFilterControl';
-import ControlRow from '../../explore/components/ControlRow';
-import Control from '../../explore/components/Control';
-import controls from '../../explore/controls';
-import { getExploreUrl } from '../../explore/exploreUtils';
-import OnPasteSelect from '../../components/Select/OnPasteSelect';
-import { getDashboardFilterKey } from '../../dashboard/util/getDashboardFilterKey';
-import { getFilterColorMap } from '../../dashboard/util/dashboardFiltersColorMap';
+import DateFilterControl from 'src/explore/components/controls/DateFilterControl';
+import ControlRow from 'src/explore/components/ControlRow';
+import Control from 'src/explore/components/Control';
+import controls from 'src/explore/controls';
+import { getExploreUrl } from 'src/explore/exploreUtils';
+import OnPasteSelect from 'src/components/Select/OnPasteSelect';
+import { getDashboardFilterKey } from 'src/dashboard/util/getDashboardFilterKey';
+import { getFilterColorMap } from 'src/dashboard/util/dashboardFiltersColorMap';
 import {
   FILTER_CONFIG_ATTRIBUTES,
   FILTER_OPTIONS_LIMIT,
   TIME_FILTER_LABELS,
-} from '../../explore/constants';
-import FilterBadgeIcon from '../../components/FilterBadgeIcon';
+} from 'src/explore/constants';
+import FilterBadgeIcon from 'src/components/FilterBadgeIcon';
 
 import './FilterBox.less';
 
diff --git a/superset-frontend/webpack.config.js b/superset-frontend/webpack.config.js
index 500a129b49927..081b98fdaa9f8 100644
--- a/superset-frontend/webpack.config.js
+++ b/superset-frontend/webpack.config.js
@@ -55,9 +55,12 @@ const output = {
 if (isDevMode) {
   output.filename = '[name].[hash:8].entry.js';
   output.chunkFilename = '[name].[hash:8].chunk.js';
-} else {
+} else if (nameChunks) {
   output.filename = '[name].[chunkhash].entry.js';
   output.chunkFilename = '[name].[chunkhash].chunk.js';
+} else {
+  output.filename = '[name].[chunkhash].entry.js';
+  output.chunkFilename = '[chunkhash].chunk.js';
 }
 
 const plugins = [
@@ -199,6 +202,8 @@ const config = {
     sideEffects: true,
     splitChunks: {
       chunks: 'all',
+      // increase minSize for devMode to 1000kb because of sourcemap
+      minSize: isDevMode ? 1000000 : 20000,
       name: nameChunks,
       automaticNameDelimiter: '-',
       minChunks: 2,
@@ -214,6 +219,8 @@ const config = {
               'react',
               'react-dom',
               'prop-types',
+              'react-prop-types',
+              'prop-types-extra',
               'redux',
               'react-redux',
               'react-hot-loader',
@@ -221,6 +228,7 @@ const config = {
               'react-sortable-hoc',
               'react-virtualized',
               'react-table',
+              'react-ace',
               '@hot-loader.*',
               'webpack.*',
               '@?babel.*',
@@ -228,20 +236,17 @@ const config = {
               'antd',
               '@ant-design.*',
               '.*bootstrap',
+              'react-bootstrap-slider',
               'moment',
               'jquery',
               'core-js.*',
               '@emotion.*',
-              'd3.*',
+              'd3',
+              'd3-(array|color|scale|interpolate|format|selection|collection|time|time-format)',
             ].join('|')})/`,
           ),
         },
         // bundle large libraries separately
-        brace: {
-          name: 'brace',
-          test: /\/node_modules\/(brace|react-ace)\//,
-          priority: 40,
-        },
         mathjs: {
           name: 'mathjs',
           test: /\/node_modules\/mathjs\//,