#2752 Tk Cocoa zombie toplevel

[Tom Goddard]

If a toplevel window is made a transient of another toplevel (master) and the master window is withdrawn, a focus and grab on the transient can cause the master to be remapped without Tk knowing about it (winfo ismapped returns 0). The master should not be mapped. After deleting the transient window no button clicks have any effect on any widgets in the master. The close, iconify and maximize buttons on the master window frame also don't work. So the master window is dead and cannot be closed using the mouse. This happens with Tk Cocoa Jan 8, 2010 source code, but behaves correctly in Tk Carbon 8.5.8 (master is not mapped), and on Linux and Windows Tk 8.5.8.

Here is a Wish script demonstrating the problem

wm withdraw .
toplevel .m
wm transient .m .
focus .m
grab .m
destroy .m
winfo ismapped .

Oddly the problem does not appear if this script is run as a command-line argument to Wish. Instead the commands need to be typed one at a time to Wish.

[Kevin Walzer]

In Tk-Cocoa, the focus and grab commands seem to generate a modal session for the window, which "unhides" the main Cocoa app window (though Tk still thinks it's not mapped). See http://stackoverflow.com/questions/4484521/showing-a-modal-nswindow-without-activating-the-other-application-windows for an explanation of this. A fix is not clear.