Description of problem:
I have a directory called ~/icons containing a lot of jpg,gif,... files, and I start gthumb as follows:

gthumb ~/icons

All is OK, and each graphics file is shown correctly. But if changing the view to slideshow, the whole X-Screen gets locked. Fortunately, switching to some virtual konsole by Ctrl+Alt+Fn) is possible, and the only recipe is to kill gthumb so the X-screen gets unlocked. 

Version-Release number of selected component (if applicable):
gthumb-2.11.3-1.fc13.i686

How reproducible:
See description

Steps to Reproduce:
1. gthumb <some directory with pictures>
2.View->slide show
3.
  
Actual results:
The screen becomes dark, all application windows disappear

Expected results:
Slide show

Additional info:

By killing gthumb from some virtual konsole getting rid from the lock