message: Impl the checkbox for the Developer Tools toogle menu.
diff: *
  * This source code is licensed under the MIT license which is detailed in the LICENSE.txt file.
  */
  -import { Event} from 'extraterm-extension-api';
  +import { Event, CustomizedCommand} from 'extraterm-extension-api';
  import * as Electron from 'electron';
  import * as _ from 'lodash';
  import * as SourceMapSupport from 'source-map-support';
  @@ -353,7 +353,8 @@ function startUpExtensions() {
  function registerCommands(extensionManager: ExtensionManager): void {
  const commands = extensionManager.getExtensionContextByName("internal-commands").commands;
  - commands.registerCommand("extraterm:window.toggleDeveloperTools", commandToogleDeveloperTools);
  + commands.registerCommand("extraterm:window.toggleDeveloperTools", commandToogleDeveloperTools,
  + customizeToogleDeveloperTools);
  commands.registerCommand("extraterm:window.reloadCss", commandReloadThemeContents);
  commands.registerCommand("extraterm:application.openCommandPalette", commandOpenCommandPalette);
  @@ -365,10 +366,16 @@ function registerCommands(extensionManager: ExtensionManager): void {
  function commandToogleDeveloperTools(): void {
  const developerToolMenu = <CheckboxMenuItem> document.getElementById("developer_tools");
  - developerToolMenu.checked = ! developerToolMenu.checked;
  WebIpc.devToolsRequest(developerToolMenu.checked);
  }
  +function customizeToogleDeveloperTools(): CustomizedCommand {
  + const developerToolMenu = <CheckboxMenuItem> document.getElementById("developer_tools");
  + return {
  + checked: developerToolMenu.checked
  + };
  +}
  +
  function commandReloadThemeContents(): void {
  reloadThemeContents();
  }
  