Logged In: YES 
user_id=543663

I fixed a bug in the original patch: when destroying a
window which had Variable instances attached which in turn
had trace commands bound, Tkinter.py was trying to delete
the commands twice, as the command was mentioned in Variable
instance _tclCommands and _root()._tcl_Commands.

Also fixed 4 more leaks occurring when TclError is raised
after a callback has been created.

I have added 6 tests to tkleak.py to test the additional 4
fixes.

The patch is against 50704, hope it helps.

Thanks for your hard work, and for accepting my other
Tkinter.py patch.