The 'Theme changed' message is maddening.  I verified that is was not occurring without this patch.  I made sure all widgets were passed cls.root as master, and that all were delected.  Running the class with "def test_dummy(self): pass" and all other methods commented out did not result in the message.  So setup and teardown do not, in themselves, cause it.  Running the first test, test_simple up to the point where a replace function is caused did not trigger the message.  Running most any replace funcition does trigger.  The base dialog and search tests do not trigger, so merely creating an engine did not.  One new thing in replace test is tests using REs.

Anyway, pushed slightly modified files.  I am no longer backporting 'routine' patches to 2.7.