I have finally signed up because I think I may have something to add here.
I have found that switching back and forth between metacity and compiz to correct Google Earth causes errors and instability. Also when returning to compiz, conky only displays on 1 desktop on my desktop cube.
Below is the error compiz returns when reopening from metacity. Apparently this error is a fairly decent issue all its own.
Also I believe this issue is related to the problems with compiz and Opengl viewports. I don't know if anyone is making these connections, I'm just trying to brainstorm. I think that this is a localized issue.
/usr/bin/compiz.real (video) - Warn: No 8 bit GLX pixmap format, disabling YV12 image format
GConf backend: There is an unsupported value at path /apps/compiz/plugins/scale/allscreens/options/initiate_edge. Settings from this path won't be read. Try to remove that value so that operation can continue properly.
I think compiz.real is the file that controls transparency or at least has something to do with it, correct me if I'm wrong. Perhaps there is some sort of error with it, or an error with the files that point to it.
I have a temporary fix that may work better than what I've seen suggested, which was:
you@yourhouse:~$ metacity --replace
I left compiz on, went to System>Preferences>Advanced Desktop Effects Settings, Then Desktop>Desktop Cube>Transparent Cube Tab and adjusted the transparency to 100%. Where Google Earth before was completely unusable, I now only get a few tics and tweaks.
Does anyone else run a transparent cube desktop? If so, this might work for you.