bpo-39885: Make IDLE context menu cut and copy work again (GH-18951)


Leave selection when right click within.  This exception to clearing selections when right-clicking was omitted from the previous commit, 4ca060d.  I did not realize that this completely disabled the context menu entries, and  I should have merged a minimal fix immediately.  An automated test should follow.
(cherry picked from commit 97e4e0f53d6690db6b942678489716a30925b8af)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
4 files changed