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>
diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
index 709008f..7982afa 100644
--- a/Lib/idlelib/NEWS.txt
+++ b/Lib/idlelib/NEWS.txt
@@ -12,8 +12,9 @@
 bpo-27115: For 'Go to Line', use a Query entry box subclass with
 IDLE standard behavior and improved error checking.
 
-bpo-39885: Since clicking to get an IDLE context menu moves the
-cursor, any text selection should be and now is cleared.
+bpo-39885: When a context menu is invoked by right-clicking outside
+of a selection, clear the selection and move the cursor.  Cut and
+Copy require that the click be within the selection.
 
 bpo-39852: Edit "Go to line" now clears any selection, preventing
 accidental deletion.  It also updates Ln and Col on the status bar.