bpo-33610: IDLE's code-context always shows current context immediately (GH-14821)

Eliminate delay of up to 100ms and accompanying visual artifact.
Fix bug of never showing context when hide and show.

1 files changed, 7 insertions, 4 deletions

diff --git a/Lib/idlelib/codecontext.py b/Lib/idlelib/codecontext.py
index 9bd0fa1753..3103391cfe 100644
--- a/Lib/idlelib/codecontext.py
+++ b/Lib/idlelib/codecontext.py
@@ -63,10 +63,13 @@ class CodeContext:
         """
         self.editwin = editwin
         self.text = editwin.text
+        self._reset()
+
+    def _reset(self):
         self.context = None
+        self.t1 = None
         self.topvisible = 1
         self.info = [(0, -1, "", False)]
-        self.t1 = None
 
     @classmethod
     def reload(cls):
@@ -112,17 +115,17 @@ class CodeContext:
                 padx=padx, border=border, relief=SUNKEN, state='disabled')
             self.update_highlight_colors()
             self.context.bind('<ButtonRelease-1>', self.jumptoline)
+            # Get the current context and initiate the recurring update event.
+            self.timer_event()
             # Pack the context widget before and above the text_frame widget,
             # thus ensuring that it will appear directly above text_frame.
             self.context.pack(side=TOP, fill=X, expand=False,
                               before=self.editwin.text_frame)
             menu_status = 'Hide'
-            self.t1 = self.text.after(self.UPDATEINTERVAL, self.timer_event)
         else:
             self.context.destroy()
-            self.context = None
             self.text.after_cancel(self.t1)
-            self.t1 = None
+            self._reset()
             menu_status = 'Show'
         self.editwin.update_menu_label(menu='options', index='* Code Context',
                                        label=f'{menu_status} Code Context')