diff --git a/framework/core/js/src/common/components/ItemList.tsx b/framework/core/js/src/common/components/ItemList.tsx
new file mode 100644
index 0000000000..8b29e6b38c
--- /dev/null
+++ b/framework/core/js/src/common/components/ItemList.tsx
@@ -0,0 +1,55 @@
+import ItemListUtil from '../utils/ItemList';
+import Component from '../Component';
+import type Mithril from 'mithril';
+import listItems from '../helpers/listItems';
+
+export interface IItemListAttrs {
+  /** Unique key for the list. Use the convention of `componentName.listName` */
+  key: string;
+  /** The context of the list. Usually the component instance. Will be automatically set if not provided. */
+  context?: any;
+  /** Optionally, the element tag to wrap each item in. Defaults to none. */
+  wrapper?: string;
+}
+
+export default class ItemList<CustomAttrs extends IItemListAttrs = IItemListAttrs> extends Component<CustomAttrs> {
+  view(vnode: Mithril.Vnode<CustomAttrs>) {
+    const items = this.items(vnode.children).toArray();
+
+    return vnode.attrs.wrapper ? listItems(items, vnode.attrs.wrapper) : items;
+  }
+
+  items(children: Mithril.ChildArrayOrPrimitive | undefined): ItemListUtil<Mithril.Children> {
+    const items = new ItemListUtil<Mithril.Children>();
+
+    let priority = 10;
+
+    this.validateChildren(children)
+      .reverse()
+      .forEach((child: Mithril.Vnode<any, any>) => {
+        items.add(child.key!.toString(), child, (priority += 10));
+      });
+
+    return items;
+  }
+
+  private validateChildren(children: Mithril.ChildArrayOrPrimitive | undefined): Mithril.Vnode<any, any>[] {
+    if (!children) return [];
+
+    children = Array.isArray(children) ? children : [children];
+    children = children.filter((child: Mithril.Children) => child !== null && child !== undefined);
+
+    // It must be a Vnode array
+    children.forEach((child: Mithril.Children) => {
+      if (typeof child !== 'object' || !('tag' in child!)) {
+        throw new Error(`[${this.attrs.key}] The ItemList component requires a valid mithril Vnode array. Found: ${typeof child}.`);
+      }
+
+      if (!child.key) {
+        throw new Error('The ItemList component requires a unique key for each child in the list.');
+      }
+    });
+
+    return children as Mithril.Vnode<any, any>[];
+  }
+}
diff --git a/framework/core/js/src/common/extenders/ItemList.ts b/framework/core/js/src/common/extenders/ItemList.ts
new file mode 100644
index 0000000000..9edd93d53e
--- /dev/null
+++ b/framework/core/js/src/common/extenders/ItemList.ts
@@ -0,0 +1,89 @@
+import type IExtender from './IExtender';
+import type { IExtensionModule } from './IExtender';
+import type Application from '../Application';
+import type Mithril from 'mithril';
+import type { IItemObject } from '../utils/ItemList';
+import { extend } from '../extend';
+import ItemListComponent from '../components/ItemList';
+
+type LazyContent<T> = (context: T) => Mithril.Children;
+
+/**
+ * The `ItemList` extender allows you to add, remove, and replace items in an
+ * `ItemList` component. Each ItemList has a unique key, which is used to
+ * identify it.
+ *
+ * @example
+ * ```tsx
+ * import Extend from 'flarum/common/extenders';
+ *
+ * export default [
+ *   new Extend.ItemList<PageStructure>('PageStructure.mainItems')
+ *     .add('test', (context) => app.forum.attribute('baseUrl'), 400)
+ *     .setContent('hero', (context) => <div>My new content</div>)
+ *     .setPriority('hero', 0)
+ *     .remove('hero')
+ * ]
+ * ```
+ */
+export default class ItemList<T = Component<any>> implements IExtender {
+  protected key: string;
+  protected additions: Array<IItemObject<LazyContent<T>>> = [];
+  protected removals: string[] = [];
+  protected contentReplacements: Record<string, LazyContent<T>> = {};
+  protected priorityReplacements: Record<string, number> = {};
+
+  constructor(key: string) {
+    this.key = key;
+  }
+
+  add(itemName: string, content: LazyContent<T>, priority: number = 0) {
+    this.additions.push({ itemName, content, priority });
+
+    return this;
+  }
+
+  remove(itemName: string) {
+    this.removals.push(itemName);
+
+    return this;
+  }
+
+  setContent(itemName: string, content: LazyContent<T>) {
+    this.contentReplacements[itemName] = content;
+
+    return this;
+  }
+
+  setPriority(itemName: string, priority: number) {
+    this.priorityReplacements[itemName] = priority;
+
+    return this;
+  }
+
+  extend(app: Application, extension: IExtensionModule) {
+    const { key, additions, removals, contentReplacements, priorityReplacements } = this;
+
+    extend(ItemListComponent.prototype, 'items', function (this: ItemListComponent, items) {
+      if (key !== this.attrs.key) return;
+
+      const safeContent = (content: Mithril.Children) => (typeof content === 'string' ? [content] : content);
+
+      for (const itemName of removals) {
+        items.remove(itemName);
+      }
+
+      for (const { itemName, content, priority } of additions) {
+        items.add(itemName, safeContent(content(this.attrs.context)), priority);
+      }
+
+      for (const [itemName, content] of Object.entries(contentReplacements)) {
+        items.setContent(itemName, safeContent(content(this.attrs.context)));
+      }
+
+      for (const [itemName, priority] of Object.entries(priorityReplacements)) {
+        items.setPriority(itemName, priority);
+      }
+    });
+  }
+}
diff --git a/framework/core/js/src/common/extenders/index.ts b/framework/core/js/src/common/extenders/index.ts
index e2d5dda532..a989310a2d 100644
--- a/framework/core/js/src/common/extenders/index.ts
+++ b/framework/core/js/src/common/extenders/index.ts
@@ -2,12 +2,14 @@ import Model from './Model';
 import PostTypes from './PostTypes';
 import Routes from './Routes';
 import Store from './Store';
+import ItemList from './ItemList';
 
 const extenders = {
   Model,
   PostTypes,
   Routes,
   Store,
+  ItemList,
 };
 
 export default extenders;
diff --git a/framework/core/js/src/forum/components/DiscussionPage.tsx b/framework/core/js/src/forum/components/DiscussionPage.tsx
index 343f56e7bd..1e564c43ac 100644
--- a/framework/core/js/src/forum/components/DiscussionPage.tsx
+++ b/framework/core/js/src/forum/components/DiscussionPage.tsx
@@ -5,7 +5,6 @@ import Page, { IPageAttrs } from '../../common/components/Page';
 import ItemList from '../../common/utils/ItemList';
 import DiscussionHero from './DiscussionHero';
 import DiscussionListPane from './DiscussionListPane';
-import LoadingIndicator from '../../common/components/LoadingIndicator';
 import SplitDropdown from '../../common/components/SplitDropdown';
 import listItems from '../../common/helpers/listItems';
 import DiscussionControls from '../utils/DiscussionControls';
diff --git a/framework/core/js/src/forum/components/PageStructure.tsx b/framework/core/js/src/forum/components/PageStructure.tsx
index c9bf025d06..c349e7d376 100644
--- a/framework/core/js/src/forum/components/PageStructure.tsx
+++ b/framework/core/js/src/forum/components/PageStructure.tsx
@@ -2,8 +2,8 @@ import Component from '../../common/Component';
 import type { ComponentAttrs } from '../../common/Component';
 import type Mithril from 'mithril';
 import classList from '../../common/utils/classList';
-import ItemList from '../../common/utils/ItemList';
 import LoadingIndicator from '../../common/components/LoadingIndicator';
+import ItemList from '../../common/components/ItemList';
 
 export interface PageStructureAttrs extends ComponentAttrs {
   hero?: () => Mithril.Children;
@@ -21,73 +21,44 @@ export default class PageStructure<CustomAttrs extends PageStructureAttrs = Page
 
     this.content = vnode.children;
 
-    return <div className={classList('Page', className)}>{this.rootItems().toArray()}</div>;
-  }
-
-  rootItems(): ItemList<Mithril.Children> {
-    const items = new ItemList<Mithril.Children>();
-
-    items.add('pane', this.providedPane(), 100);
-    items.add('main', this.main(), 10);
-
-    return items;
-  }
-
-  mainItems(): ItemList<Mithril.Children> {
-    const items = new ItemList<Mithril.Children>();
-
-    items.add('hero', this.providedHero(), 100);
-    items.add('container', this.container(), 10);
-
-    return items;
-  }
-
-  loadingItems(): ItemList<Mithril.Children> {
-    const items = new ItemList<Mithril.Children>();
-
-    items.add('spinner', <LoadingIndicator display="block" />, 100);
-
-    return items;
-  }
-
-  main(): Mithril.Children {
-    return <div className="Page-main">{this.attrs.loading ? this.loadingItems().toArray() : this.mainItems().toArray()}</div>;
-  }
-
-  containerItems(): ItemList<Mithril.Children> {
-    const items = new ItemList<Mithril.Children>();
-
-    items.add('sidebar', this.sidebar(), 100);
-    items.add('content', this.providedContent(), 10);
-
-    return items;
-  }
-
-  container(): Mithril.Children {
-    return <div className="Page-container container">{this.containerItems().toArray()}</div>;
-  }
-
-  sidebarItems(): ItemList<Mithril.Children> {
-    const items = new ItemList<Mithril.Children>();
-
-    items.add('sidebar', (this.attrs.sidebar && this.attrs.sidebar()) || null, 100);
-
-    return items;
-  }
-
-  sidebar(): Mithril.Children {
-    return <div className="Page-sidebar">{this.sidebarItems().toArray()}</div>;
-  }
-
-  providedPane(): Mithril.Children {
-    return <div className="Page-pane">{(this.attrs.pane && this.attrs.pane()) || null}</div>;
-  }
-
-  providedHero(): Mithril.Children {
-    return <div className="Page-hero">{(this.attrs.hero && this.attrs.hero()) || null}</div>;
-  }
-
-  providedContent(): Mithril.Children {
-    return <div className="Page-content">{this.content}</div>;
+    return (
+      <div className={classList('Page', className)}>
+        <ItemList key="PageStructure.rootItems" context={this}>
+          <div key="pane" className="Page-pane">
+            {(this.attrs.pane && this.attrs.pane()) || null}
+          </div>
+
+          <div key="main" className="Page-main">
+            {this.attrs.loading ? (
+              <ItemList key="PageStructure.loadingItems" context={this}>
+                <LoadingIndicator key="spinner" display="block" />
+              </ItemList>
+            ) : (
+              <ItemList key="PageStructure.mainItems" context={this}>
+                <div key="hero" className="Page-hero">
+                  {(this.attrs.hero && this.attrs.hero()) || null}
+                </div>
+
+                <div key="container" className="Page-container container">
+                  <div key="sidebar" className="Page-sidebar">
+                    <ItemList key="PageStructure.sidebarItems" context={this}>
+                      {this.attrs.sidebar && (
+                        <div key="provided" className="Page-sidebar-main">
+                          {this.attrs.sidebar()}
+                        </div>
+                      )}
+                    </ItemList>
+                  </div>
+
+                  <div key="content" className="Page-content">
+                    {this.content}
+                  </div>
+                </div>
+              </ItemList>
+            )}
+          </div>
+        </ItemList>
+      </div>
+    );
   }
 }
diff --git a/framework/core/less/forum/DiscussionPage.less b/framework/core/less/forum/DiscussionPage.less
index f4626d786c..c2b9c276a8 100644
--- a/framework/core/less/forum/DiscussionPage.less
+++ b/framework/core/less/forum/DiscussionPage.less
@@ -40,6 +40,10 @@
 
       &-sidebar {
         margin-top: 0;
+
+        &-main {
+          height: 100%;
+        }
       }
     }
   }