commit 9beaef6225cdae972b1cccd5310828cc29bf9d33
author Terry Jan Reedy <tjreedy@udel.edu> Thu Aug 02 22:50:01 2018 -0400
committer GitHub <noreply@github.com> Thu Aug 02 22:50:01 2018 -0400
tree 3e4f49b0b325ea8431dde02c298c06eb6201a9d0
parent bcd1d971b66f529cbd450aca438275b868031605

 bpo-34275: Make IDLE calltips always visible on Mac.  (GH-8639)

Some MacOS-tk combinations need .update_idletasks().
The call is both unneeded and innocuous on Linux and Windows.
Patch by Kevin Waltzer.

Lib/idlelib/calltip_w.py

diff --git a/Lib/idlelib/calltip_w.py b/Lib/idlelib/calltip_w.py
index 34531f4..1b1ffc5 100644
--- a/Lib/idlelib/calltip_w.py
+++ b/Lib/idlelib/calltip_w.py
@@ -72,6 +72,7 @@
                            background="#ffffe0", relief=SOLID, borderwidth=1,
                            font = self.widget['font'])
         self.label.pack()
+        tw.update_idletasks()
         tw.lift()  # work around bug in Tk 8.5.18+ (issue #24570)
 
         self.checkhideid = self.widget.bind(CHECKHIDE_VIRTUAL_EVENT_NAME,