Subject: bug#40278: 27.0.90; Flickering in Windows 10

From: Noam Postavsky <[email-masked]>
Date: Wed, 01 Apr 2020 10:25:16 -0400

>> Emacs frame partially covered by an Emacs frame: Nothing happens. Mouse input
>> does not seem to go anywhere.

Seems to work fine for me.  I see the "normal" flickering, no slow-paint
rectangle.

>> Emacs frame partially covered by a Windows explorer window: Emacs scrolls
>> normally, that is, in my case there is some flickering. But nothing like what
>> happens with a child frame.

Same here.

martin rudalics <[email-masked]> writes:

> What happens when you write
>
> (defun open-test ()
>   (display-buffer-in-child-frame
>    (get-buffer-create "test child-frame")
>    '((child-frame-parameters . ((tool-bar-lines . 0)
> 				(width . 20)
>                                 (height . 10)
>                                 (top . 200)
>                                 (left . 100))))))

Doesn't make a difference, I still see the slow-paint rectangle.

=======================

At any rate, if I've understood the responses from Eli, it sounds like
there isn't any bug here, just that we haven't implemented double
buffering for Windows.