diff --git a/packages/ckeditor5-ui/package.json b/packages/ckeditor5-ui/package.json
index a992776b9e3..f71d705e9ec 100644
--- a/packages/ckeditor5-ui/package.json
+++ b/packages/ckeditor5-ui/package.json
@@ -27,6 +27,7 @@
     "@ckeditor/ckeditor5-list": "^19.0.1",
     "@ckeditor/ckeditor5-mention": "^19.0.1",
     "@ckeditor/ckeditor5-paragraph": "^19.1.0",
+    "@ckeditor/ckeditor5-horizontal-line": "^19.0.1",
     "@ckeditor/ckeditor5-typing": "^19.0.1"
   },
   "engines": {
diff --git a/packages/ckeditor5-ui/src/toolbar/balloon/balloontoolbar.js b/packages/ckeditor5-ui/src/toolbar/balloon/balloontoolbar.js
index 7ad174b3d8d..f4d86033f0e 100644
--- a/packages/ckeditor5-ui/src/toolbar/balloon/balloontoolbar.js
+++ b/packages/ckeditor5-ui/src/toolbar/balloon/balloontoolbar.js
@@ -209,6 +209,8 @@ export default class BalloonToolbar extends Plugin {
 	 */
 	show() {
 		const editor = this.editor;
+		const selection = editor.model.document.selection;
+		const schema = editor.model.schema;
 
 		// Do not add the toolbar to the balloon stack twice.
 		if ( this._balloon.hasView( this.toolbarView ) ) {
@@ -216,7 +218,13 @@ export default class BalloonToolbar extends Plugin {
 		}
 
 		// Do not show the toolbar when the selection is collapsed.
-		if ( editor.model.document.selection.isCollapsed ) {
+		if ( selection.isCollapsed ) {
+			return;
+		}
+
+		// Do not show the toolbar when there is more than one range in the selection and they fully contain object elements.
+		// See https://github.com/ckeditor/ckeditor5/issues/6443.
+		if ( selectionContainsOnlyMultipleObjects( selection, schema ) ) {
 			return;
 		}
 
@@ -356,6 +364,26 @@ function getBalloonPositions( isBackward ) {
 	];
 }
 
+// Returns "true" when the selection has multiple ranges and each range contains an object
+// and nothing else.
+//
+// @private
+// @param {module:engine/model/selection~Selection} selection
+// @param {module:engine/model/schema~Schema} schema
+// @returns {Boolean}
+function selectionContainsOnlyMultipleObjects( selection, schema ) {
+	// It doesn't contain multiple objects if there is only one range.
+	if ( selection.rangeCount === 1 ) {
+		return false;
+	}
+
+	return [ ...selection.getRanges() ].every( range => {
+		const element = range.getContainedElement();
+
+		return element && schema.isObject( element );
+	} );
+}
+
 /**
  * Contextual toolbar configuration. Used by the {@link module:ui/toolbar/balloon/balloontoolbar~BalloonToolbar}
  * feature.
diff --git a/packages/ckeditor5-ui/tests/toolbar/balloon/balloontoolbar.js b/packages/ckeditor5-ui/tests/toolbar/balloon/balloontoolbar.js
index 02a1d4c55ab..68cf6118f87 100644
--- a/packages/ckeditor5-ui/tests/toolbar/balloon/balloontoolbar.js
+++ b/packages/ckeditor5-ui/tests/toolbar/balloon/balloontoolbar.js
@@ -14,6 +14,7 @@ import Bold from '@ckeditor/ckeditor5-basic-styles/src/bold';
 import Italic from '@ckeditor/ckeditor5-basic-styles/src/italic';
 import Underline from '@ckeditor/ckeditor5-basic-styles/src/underline';
 import Paragraph from '@ckeditor/ckeditor5-paragraph/src/paragraph';
+import HorizontalLine from '@ckeditor/ckeditor5-horizontal-line/src/horizontalline';
 import global from '@ckeditor/ckeditor5-utils/src/dom/global';
 import ResizeObserver from '@ckeditor/ckeditor5-utils/src/dom/resizeobserver';
 
@@ -55,7 +56,7 @@ describe( 'BalloonToolbar', () => {
 
 		return ClassicTestEditor
 			.create( editorElement, {
-				plugins: [ Paragraph, Bold, Italic, BalloonToolbar ],
+				plugins: [ Paragraph, Bold, Italic, BalloonToolbar, HorizontalLine ],
 				balloonToolbar: [ 'bold', 'italic' ]
 			} )
 			.then( newEditor => {
@@ -374,6 +375,15 @@ describe( 'BalloonToolbar', () => {
 			sinon.assert.notCalled( balloonAddSpy );
 		} );
 
+		// https://github.com/ckeditor/ckeditor5/issues/6443
+		it( 'should not add the #toolbarView to the #_balloon when the selection contains more than one fully contained object', () => {
+			// This is for multi cell selection in tables.
+			setData( model, '[<horizontalLine></horizontalLine>]<paragraph>foo</paragraph>[<horizontalLine></horizontalLine>]' );
+
+			balloonToolbar.show();
+			sinon.assert.notCalled( balloonAddSpy );
+		} );
+
 		it( 'should not add #toolbarView to the #_balloon when all components inside #toolbarView are disabled', () => {
 			Array.from( balloonToolbar.toolbarView.items ).forEach( item => {
 				item.isEnabled = false;