I have an odd problem where a one-pixel high white line is displayed through certain letters of text. Almost always only a single character type is affected at once, and only in one font size (though that size can change over time). Most of the time things are fine, but this happens several times a day. It's been happening ever since I upgraded to 10.10.
I have noticed few patterns: It might be a problem with Firefox (I'm currently using the nightly ppa, but it occurred in 3.6 also) - but this could just be because I spend most of my time on my computer either at a browser or text editors. I seem to remember it happening with the buttons on various Gnome dialogs. It never occurs in text I've typed, be it an email, url bar, etc. In Firefox it happens across tabs, and the problem remains even if they are closed or reloaded; only restarting the program can fix it.
Two examples (in the first, only the larger "r" is corrupted):
Any help would be appreciated, thanks.
Edit: I've since noticed that I can (sometimes) make the fonts appear correctly by zooming in/out all the way and returning to the default in Firefox (one or two steps, then going back, does nothing) seems to make the problem go away - at least temporarily until the next time the letters feel like being corrupted.
Edit 2: I figure it's worth noting that the solution below doesn't fully work for me any longer (I'm now using Ubuntu 11.10). It does significantly reduce the frequency of this problem occurring, so it's quite useful, but the corruption does still occasionally appear.
Edit 3: Still around in 12.04. The fix provided by Vanni works perfectly now for me, but apparently doesn't for some.