Two Monitors: why only one works?

Both my home-PC and my portable PC are ATI card based: the first ATI9200 and the second ATI7500.
Both support dual monitor.

When I run applications I am writing with OpenGl (via Delphi5), those app work properly only on monitor 1. if I move the app window on the monitor nr. 2, it remains a gray window.

Everything goes bad the same way if I tried do enlarge the Opengl App window trought monitor 1 to monitor 2.

Any suggetstion ???

If I changed the video card to a nVidia, will this problem be solved by itself ???


It works on my computer using a 9500 Pro, try upgrading to catalyst 4.8

I have got a similar problem when using my Matrox P650 card on two monitors.

If I recall correctly, the one-monitor restriction has something to do with the Windows kernel. Newer drivers can circumvent that restriction somehow, but I heard its a rather ugly hack that doesnt work in all cases.

This is only what I heard, so maybe someone else has a better inside and can correct me where I am mistaken.


I’m currently having the same problem. Working on my laptop with an ATI card, I can see my OpenGL display on Screen one, but not on Screen two. The funny thing is, that when I move the Window and one half is on screen 1 and the other half on screen 2 it still works on both. But when the last pixel column moves to screen 2, it grays.
Customers of our software reported the same for nVidia Quadro.

What I found out until now:
Other OpenGL App’s work. So it seems to be a problem with my settings. I tried a simple NeHe example which worked. The difference is -> NeHe uses ChoosePixelFormat. I use enumeration of pixel formats (for some special reasons). So I fear that I missed something and chose the wrong pixel format.

I’ll post more after I found out…