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From: tomas@m2cs.uu.no (Tomas Felner)
Newsgroups: comp.windows.news
Subject: Flickering canvases
Keywords: moving canvas flickering
Message-ID: <1989Nov6.111754.11056@m2cs.uu.no>
Date: 6 Nov 89 11:17:54 GMT
Organization: Modula-2 CASE Systems A/S, Oslo, Norway
Lines: 20

I have a problem with moving canvases that has been bothering me for
quite some time. The basic situation is as follows: I have a canvas
ontop of which I have another canvas, on top of which another one, etc. I
have code to grab one of those canvases with the mouse and move them around.
All the canvases on top of the grabbed canvas are then moved together
with the grabbed one. When moving this "stack of canvases" the moving of 
the bottommost canvas goes smoothly, but all the canvases on top of it
flicker like crazy! This effect appears with any stack of canvases and 
with an arbitray number of canvases on top of the bottom canvas.

Why is this so? Is there any way to avoid this? Am I doing something
wrong? Help !!!

Tomas
-- 
                          Tomas Felner
     Modula-2 CASE Systems AS  |  Internet: tomas@m2cs.uu.no
            Maridalsveien 139  |  Phone: +47 2 379784
        N-0461 Oslo 4, Norway  |  FAX: +47 2 356448