Comment 14 for bug 588155

This problem keeps appearing for me since yesterday. Just as in the bug description, when I log in, sometimes the ambiance theme doesn't load and I get the default GTK-Theme instead. I have to either log out and log back in or start the appearances window to solve this annoying issue.
Also, even tough I don't know whether this is normal or not (I usually don't fiddle around with appearance settings, but use the defaults instead), when I'm selecting ambiance, after restart or log in-log out it is set to "custom". Again, I have no clue if this is relevant.
I'm using Ubuntu 64bit desktop edition on an Asus EeePC 1005PE.