bpo-39885: IDLE: Leave selection when right click within

This exception was omitted from previous commit, 4ca060d.
python · terryjreedy · May 29, 2020 · Mar 12, 2020 · Mar 16, 2020 · Mar 16, 2020
commit 77814484608ca81eb227666d095c7118d6aeda9b
diff --git a/Lib/idlelib/NEWS.txt b/Lib/idlelib/NEWS.txt
@@ -6,8 +6,8 @@ Released on 2020-10-05?
 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 clicking outside of a
+selection, clear the selection and move the cursor.
 
 bpo-39852: Edit "Go to line" now clears any selection, preventing
 accidental deletion.  It also updates Ln and Col on the status bar.

diff --git a/Lib/idlelib/editor.py b/Lib/idlelib/editor.py
@@ -499,15 +499,23 @@ def handle_yview(self, event, *args):
     rmenu = None
 
     def right_menu_event(self, event):
-        self.text.tag_remove("sel", "1.0", "end")
-        self.text.mark_set("insert", "@%d,%d" % (event.x, event.y))
+        text = self.text
+        newdex = text.index(f'@{event.x},{event.y}')
+        try:
+            in_selection = (text.compare('sel.first', '<=', newdex) and
+                           text.compare(newdex, '<=',  'sel.last'))
+        except TclError:
+            in_selection = False
+        if not in_selection:
+            text.tag_remove("sel", "1.0", "end")
+        text.mark_set("insert", newdex)
         if not self.rmenu:
             self.make_rmenu()
         rmenu = self.rmenu
         self.event = event
         iswin = sys.platform[:3] == 'win'
         if iswin:
-            self.text.config(cursor="arrow")
+            text.config(cursor="arrow")
 
         for item in self.rmenu_specs:
             try:
@@ -520,7 +528,6 @@ def right_menu_event(self, event):
             state = getattr(self, verify_state)()
             rmenu.entryconfigure(label, state=state)
 
-
         rmenu.tk_popup(event.x_root, event.y_root)
         if iswin:
             self.text.config(cursor="ibeam")

diff --git a/Misc/NEWS.d/next/IDLE/2020-03-08-14-27-36.bpo-39885.29ERiR.rst b/Misc/NEWS.d/next/IDLE/2020-03-08-14-27-36.bpo-39885.29ERiR.rst
@@ -1,2 +1,2 @@
-Since clicking to get an IDLE context menu moves the cursor,
-any text selection should be and now is cleared.
+When a context menu is invoked by clicking outside of a selection,
+clear the selection and move the cursor.