How to display an error message when a tabbedUI button fails to open a Grid?

From what I can tell, the TabbedUI builder does not create the correct JavaScript for opening a Grid. To see what I mean, try this:

- Run your tabbedUI application on your development box.
- Go into the AA IDE and turn off your dev server.
- Click a tabbedUI button that opens a Grid.
- You will see a "Please wait..." message that never goes away.

The JavaScript code knows the server is not available and it should display a message, but it does not. Have I configured my TabbedUI incorrectly?

If you do the same thing for a UX, the "Please wait..." message will disappear, but no message will be displayed. Also, if you have the browser's Developer Tools turned on you will see the AA library generates a "cannot read property '_executeEvent' of undefined".

The problem with opening Grids from the TabbedUI is that AA is not setting the following two properties prior to trying to open the component:
go.ajaxFailedMessage
go.ajaxCallbackTimeout

The problem with calling a UX is that an error message is not displayed and that there is an error in the AA library as shown by Developer Tools.

I do not see a way to convert the TabbedUI button actions into plain javascript, like we can for regular Action JavaScript, so I am left with tweaking the functions AA places into the global 'window' object for opening the components from the tabbedUI buttons.

AA Ver 12.4.5.1 B4642.