Zotac ZBOX desktop zoomed out (icons partially not visible / task bar not visible)

I have installed Ubuntu 13.04 on a Zotac ZBOX ID88 mini PC (with Intel HD Graphics 2500)

At resolution 1920 x 1080 the desktop is zoomed out.
This is not the case with the 1600 x 900 resolution. Here no problem.

After running the Intel Linux Graphics Installer, the graphics driver repository was added.
However this did not solve the graphics problem.

What could be the cause of the unwanted zoom at 1920 x 1080?

Moved from “Misc: > Off-topic Chat” to “Support > Other Software”

Could I solve this problem with Compiz?