How to catch errors that occur during System.Windows.Forms.A

I'm trying to catch errors that occur in events that fire during the wait-for.

The error is not caught instead it is shown by the default progress dialog.

If it is not possible to catch this, is there a way to replace the default error dialog box .

def var myMenu as MainMenu. 
myMenu = new MainMenu(). 

do on error undo, retry: 
    myMenu:Show(). 
    wait-for System.Windows.Forms.Application:Run (myMenu). 
    CATCH e AS Progress.Lang.Error : 
        MESSAGE "Caught error" e:getmessage(1) skip
         e:callstack VIEW-AS ALERT-BOX. 
    END CATCH. 
end.

To run the sample:

• unzip,
• run main.p
• press the button to start the second form,
• leaving the first textbox empty throws an error.