Fix the "Developer tools" menu item

Author: sedwards2009

extraterm/src/render_process/MainWeb.ts

@@ -447,9 +447,7 @@ function startUpSessions(configDatabase: ConfigDatabaseImpl, extensionManager: E
 let developerToolMenuChecked = false;
 
 function commandToggleDeveloperTools(): void {
-  const developerToolMenu = <CheckboxMenuItem> document.getElementById("developer_tools");
-  WebIpc.devToolsRequest(developerToolMenu.checked);
-  developerToolMenuChecked = ! developerToolMenuChecked;
+  WebIpc.devToolsRequest( ! developerToolMenuChecked);
 }
 
 function customizeToggleDeveloperTools(): CustomizedCommand {
@@ -520,11 +518,8 @@ function handleThemeContentsMessage(msg: Messages.Message): void {
 
 function handleDevToolsStatus(msg: Messages.Message): void {
   const devToolsStatusMessage = <Messages.DevToolsStatusMessage> msg;
-  const developerToolMenu = <CheckboxMenuItem> document.getElementById("developer_tools");
-  if (developerToolMenu === null) {
-    return;
-  }
-  developerToolMenu.checked = devToolsStatusMessage.open;
+  developerToolMenuChecked = devToolsStatusMessage.open;
+  applicationContextMenu.render();
 }
 
 function handleClipboardRead(msg: Messages.Message): void {

extraterm/src/render_process/command/ApplicationContextMenu.ts

@@ -38,6 +38,7 @@ export class ApplicationContextMenu {
   private _contextMenuElement: ContextMenu = null
   private _menuEntries: CommandAndShortcut[] = null;
   private _contextWindowState : CommonExtensionWindowState = null;
+  private _menuType = ContextMenuType.NORMAL;
 
   constructor(private extensionManager: ExtensionManager, private keybindingsManager: KeybindingsManager) {
     this._log = getLogger("ApplicationContextMenu", this);
@@ -85,12 +86,17 @@ export class ApplicationContextMenu {
   }
 
   openAround(el: HTMLElement, menuType: ContextMenuType): void {
+    this._menuType = menuType;
     doLater( () => {
       this._updateMenu(menuType);
       this._contextMenuElement.openAround(el);
     });
   }
 
+  render(): void {
+    this._updateMenu(this._menuType);
+  }
+
   private _updateMenu(menuType: ContextMenuType): void {
     const options: CommandQueryOptions = {
       when: true