python tkinter with threading causing crash
Solution 1:
Tkinter is not thread safe; you cannot access Tkinter widgets from anywhere but the main thread. You will need to refactor your code so that QueueHandler runs in the main thread.
Solution 2:
As Bryan says Tkinter is not thread safe. Here is a modification that attempts to make it so: http://tkinter.unpythonic.net/wiki/mtTkinter
Solution 3:
Tkinter is designed to be thread-safe but isn't due to bugs, in both 2.x and 3.x.
Until fixes are released (and in older versions), you should use mtTkinter (which is designed to be a drop-in replacement) as a workaround.