This happens when I move the windows. Details:
openbox
ATI proprietary driver
no problem in OpenGL contexts
I don't want to use any compositing manager
It's not so strange, quite common in fact. Read here.
Obviously this image doesn't reproduce a real screen tearing. I found that the Gimp screen capture gave a good idea of what happens, so I tried this way to explain the issue.
You might be able to avoid this by using outline dragging instead of showing the full contents.
In Windows 7 you will find it under Control Panel/System/Advanced System Settings/
Scroll down and uncheck "Show windows content while dragging"
It might be a problem with your driver or a product of your system specifications.
I found my netbook works much better with outline dragging turned on.
Check your compiz modules; there are some "visual effects" which let your windows "wobble" when you drag them. Maybe you activated one of them.
[EDIT] Screen tearing can't be captured in a screenshot since it's an optical effect that happens only on the monitor (not in RAM). Also the effect above is too regular and has too many tear lines; with normal screen tearing, you have only a single tear (or maybe two if you move the window really fast).
Therefore, the effect must be created by some program.
[EDIT2] Again: The image above is a screenshot. That means some software on your computer creates the effect. Reason: No software in the world is able to capture the optical illusion of screen tearing which happens when two refreshes on the monitor happen while something changes. So you must look at all the programs running, check the config of your window manager, find the culprit and shut it off.
In Catalyst 11.1 appears the Tear Free Desktop option; that solves the issue.
