I HAD the same problem on a newly installed hardy heron. This is what fixed it:
Went to appearance preferences, visual effects, chose normal. Nvidia-glx started to install. After it did, this bug was gone.
I HAD the same problem on a newly installed hardy heron. This is what fixed it:
Went to appearance preferences, visual effects, chose normal. Nvidia-glx started to install. After it did, this bug was gone.