From: Alexandre Julliard <julliard@winehq.org>
Subject: Re: [PATCH] winex11.drv: Redraw window on Expose event if window surface has no region set.
Message-Id: <87ftdghq08.fsf@wine>
Date: Mon, 06 Apr 2020 12:23:19 +0200
In-Reply-To: <20200403123457.20981-1-gofmanp@gmail.com> (Paul Gofman's message of "Fri, 3 Apr 2020 15:34:57 +0300")
References: <20200403123457.20981-1-gofmanp@gmail.com>

Paul Gofman <gofmanp@gmail.com> writes:

> Otherwise the window (partially) obscured by the other window sometimes fails
> to update when the obscuring window is moved or destroyed.

That's not correct, there shouldn't be any reason to repaint the entire
window when the contents are still valid.

Note that not flushing the bits right away is deliberate, that's a
performance fix. The window will get repainted when the app waits for a
new message.

If you have a real app where this is an issue, the heuristic could maybe
be tweaked to catch that case, cf. check_for_driver_events in
dlls/user32/message.c.

-- 
Alexandre Julliard
julliard@winehq.org