Yesterday I formatted my computer and reinstall Ubuntu 11.10, then I installed gnome-shell. But Now I have a problem with the Applications Overview in gnome-shell. When I Press the button "applications" I see strange lines over the icons. I get this with the default theme too (default icons and gnome-shell theme).
I did a new installation for ubuntu but the problem remains:
Best Answer
Following the changes provided by the GNOME group, many of the "visual errors" are fixed in the following versions after the one you mentioned in your question (Assuming you have the latest one from the date you posted the answer).
A simple (HUGE) update of your Gnome shell should solve this. You can find how to install the PPA right here on askubuntu.
Here is the changes for the 3.2 Version and the 3.4 version:
Gnome 3.2 - http://library.gnome.org/misc/release-notes/3.2/
Gnome 3.4 - http://library.gnome.org/misc/release-notes/3.4/