diff --git a/.eslintignore b/.eslintignore
index a8646c40ae..6f9c09e39b 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -531,6 +531,7 @@ packages/app-mobile/components/NoteEditor/NoteEditor.js
 packages/app-mobile/components/NoteEditor/SearchPanel.js
 packages/app-mobile/components/NoteEditor/commandDeclarations.js
 packages/app-mobile/components/NoteEditor/hooks/useCodeMirrorPlugins.js
+packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.test.js
 packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.js
 packages/app-mobile/components/NoteEditor/hooks/useKeyboardVisible.js
 packages/app-mobile/components/NoteEditor/types.js
diff --git a/.gitignore b/.gitignore
index 97c85d17c9..1acac8706b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -511,6 +511,7 @@ packages/app-mobile/components/NoteEditor/NoteEditor.js
 packages/app-mobile/components/NoteEditor/SearchPanel.js
 packages/app-mobile/components/NoteEditor/commandDeclarations.js
 packages/app-mobile/components/NoteEditor/hooks/useCodeMirrorPlugins.js
+packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.test.js
 packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.js
 packages/app-mobile/components/NoteEditor/hooks/useKeyboardVisible.js
 packages/app-mobile/components/NoteEditor/types.js
diff --git a/jest.base-setup.js b/jest.base-setup.js
index 898cdcc234..2d622dc3c2 100644
--- a/jest.base-setup.js
+++ b/jest.base-setup.js
@@ -14,3 +14,22 @@ module.exports = () => {
 		global.console = jestConsole;
 	});
 };
+
+// jsdom extensions
+if (typeof document !== 'undefined') {
+	// Prevents the CodeMirror error "getClientRects is undefined".
+	// See https://github.com/jsdom/jsdom/issues/3002#issue-652790925
+	document.createRange = () => {
+		const range = new Range();
+		range.getBoundingClientRect = jest.fn();
+		range.getClientRects = () => {
+			return {
+				length: 0,
+				item: () => null,
+				[Symbol.iterator]: jest.fn(),
+			};
+		};
+
+		return range;
+	};
+}
diff --git a/packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.test.ts b/packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.test.ts
new file mode 100644
index 0000000000..be2e33345e
--- /dev/null
+++ b/packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.test.ts
@@ -0,0 +1,36 @@
+import CommandService from '@joplin/lib/services/CommandService';
+import useEditorCommandHandler from './useEditorCommandHandler';
+import commandDeclarations from '../commandDeclarations';
+import createTestEditorControl from '@joplin/editor/CodeMirror/testUtil/createEditorControl';
+import { renderHook } from '@testing-library/react-native';
+import { defaultState } from '@joplin/lib/reducer';
+
+
+describe('useEditorCommandHandler', () => {
+	beforeAll(() => {
+		const storeMock = { getState: () => defaultState, dispatch: jest.fn() };
+		CommandService.instance().initialize(storeMock, false, ()=>({}));
+
+		for (const declaration of commandDeclarations) {
+			CommandService.instance().registerDeclaration(declaration);
+		}
+	});
+	it('should support running custom commands with editor.execCommand', async () => {
+		const editor = createTestEditorControl('Test.');
+		renderHook(() => useEditorCommandHandler(editor));
+
+		const testCommandCallback = jest.fn();
+		editor.registerCommand('myCommand', testCommandCallback);
+		expect(testCommandCallback).not.toHaveBeenCalled();
+
+		// Should support running commands with arguments
+		await CommandService.instance().execute('editor.execCommand', { name: 'myCommand', args: ['a', 'b', 'c'] });
+		expect(testCommandCallback).toHaveBeenCalledTimes(1);
+		expect(testCommandCallback).toHaveBeenLastCalledWith('a', 'b', 'c');
+
+		// Should support running commands without arguments
+		await CommandService.instance().execute('editor.execCommand', { name: 'myCommand' });
+		expect(testCommandCallback).toHaveBeenCalledTimes(2);
+		expect(testCommandCallback).toHaveBeenLastCalledWith();
+	});
+});
diff --git a/packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.ts b/packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.ts
index 2428b4ce7c..7e29342451 100644
--- a/packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.ts
+++ b/packages/app-mobile/components/NoteEditor/hooks/useEditorCommandHandler.ts
@@ -1,5 +1,5 @@
 import CommandService, { CommandContext, CommandDeclaration } from '@joplin/lib/services/CommandService';
-import { EditorControl } from '../types';
+import { EditorControl } from '@joplin/editor/types';
 import { useEffect } from 'react';
 import commandDeclarations, { enabledCondition } from '../commandDeclarations';
 import Logger from '@joplin/utils/Logger';
@@ -12,9 +12,13 @@ const commandRuntime = (declaration: CommandDeclaration, editor: EditorControl)
 			// Many editor CodeMirror commands are missing the editor. prefix.
 			let commandName = declaration.name.replace(/^editor\./, '');
 
-			if (declaration.name === 'editor.execCommand') {
-				commandName = args[0];
-				args = args.slice(1);
+			if (commandName === 'execCommand') {
+				commandName = args[0]?.name;
+				args = args[0]?.args ?? [];
+
+				if (!commandName) {
+					throw new Error('editor.execCommand is missing the name of the command to execute');
+				}
 			}
 
 			if (!(await editor.supportsCommand(commandName))) {
diff --git a/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.test.ts b/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.test.ts
index 7862d114be..b22ebed9da 100644
--- a/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.test.ts
+++ b/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.test.ts
@@ -171,4 +171,16 @@ describe('CodeMirror5Emulation', () => {
 		expect(testExtensionFn1).toHaveBeenCalledTimes(1);
 		expect(testExtensionFn2).toHaveBeenCalledTimes(1);
 	});
+
+	it('defineExtension should register an extension where this points to the editor', () => {
+		const codeMirror = makeCodeMirrorEmulation('Test...');
+		let lastThis = null;
+
+		codeMirror.defineExtension('testExtension', function() {
+			lastThis = this;
+		});
+		codeMirror.execCommand('testExtension');
+
+		expect(lastThis).toBe(codeMirror);
+	});
 });
diff --git a/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.ts b/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.ts
index 2628ffbc72..64f1d8a112 100644
--- a/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.ts
+++ b/packages/editor/CodeMirror/CodeMirror5Emulation/CodeMirror5Emulation.ts
@@ -503,7 +503,7 @@ export default class CodeMirror5Emulation extends BaseCodeMirror5Emulation {
 		if (name in CodeMirror5Emulation.commands) {
 			return CodeMirror5Emulation.commands[name as (keyof typeof CodeMirror5Emulation.commands)](this);
 		} else if (typeof this._userExtensions[name] === 'function') {
-			return this._userExtensions[name](...args);
+			return this._userExtensions[name].call(this, ...args);
 		}
 	}
 }
diff --git a/packages/editor/jest.setup.js b/packages/editor/jest.setup.js
index 4071541f1f..57e3670553 100644
--- a/packages/editor/jest.setup.js
+++ b/packages/editor/jest.setup.js
@@ -1,17 +1,2 @@
 require('../../jest.base-setup.js')();
 
-// Prevents the CodeMirror error "getClientRects is undefined".
-// See https://github.com/jsdom/jsdom/issues/3002#issue-652790925
-document.createRange = () => {
-	const range = new Range();
-	range.getBoundingClientRect = jest.fn();
-	range.getClientRects = () => {
-		return {
-			length: 0,
-			item: () => null,
-			[Symbol.iterator]: jest.fn(),
-		};
-	};
-
-	return range;
-};