On strange loop example, if you try to move around slides and there's a highlighted text (in this case it's a red text), then you can see a few glitches under the box that contains the text. One thing to note about it is that these texts have some effects when you put cursor on it. I can see this bug in a similar way on Qt and Nix, and more clearly on EFL. Some investigation to figure out if this was a regression (tested on qt): r147009 - displayed with artifacts r143738 - displayed with artifacts r138818 - not even displaying r138735 - not even displaying r138476 - displayed with artifacts Looks like we've been like this forever, but at some point we've made it to stop working at all.
https://github.com/BrendanEich/Strange-Loop-2012 the latest WinCairo also reproduce the issues.
Filed another bug: Bug 241699 – TextureMapperGL: rendering glitch of a 3d transformed text in Strange-Loop-2012