Comment 6 for bug 39856

This just happened to me (its happened before, too) after I changed my graphics driver to "nv" from "nvidia" and restarted X (obviously, my resolution was lowered when using "nv")

After doing what I needed to do, I changed back to "nvidia" and back to lovely high resolution but the panel I normally have at the bottom (which is not expanded, sits in the centre with my icons) was shrunk down to 2 icons wide and I couldn't stretch it back out to its normal size and it was not at the bottom of the screen in the high resolution, it was where it was when I was running low resolution in the "nv" driver - so it was near the centre of the screen in terms of height (Y Axis) it was still in the centre in terms of X axis.

hope this helps..