Comment 36 for bug 293059

I can't find any reference in my freshly installed Ubuntu 9.04 system for the acceleration method. Xorg.conf just refers to some "configured" devices.

The font corruption problem started for me when in one user account, I tried out the various settings in the Visual Effects tab of the Appearance preferences, and later I logged into and made use of my less-privileged everyday-doing-stuff account.

It seems as if there is an off-by-one (or even two) error in the y-loop of the function that would bit from the plain rasterised glyphs to the cache of coloured and treated glyphs that ultimately get composited to the display. I'm not saying that's the cause, but if you implemented a system like that, it would produce the effect I saw.

Changing the font rendering preferences made no difference to the corrupting behaviour. Restarting the computer didn't help.

I suspected the Visual Effects settings needed to me massaged, so I logged into each of the three user accounts I have and tired out all Visual Effects settings, before going back to "None" (It's not that the other modes were slow or faulty, I just detested most of the effects and I liked the strong window snapping available in "None".)

Since then the bug has entirely disappeared. [Crosses fingers]