#12 fullscreenbutton doesnt work correctly

[Tobias Eberle]

Hello,

I have to click at the Fullscreenbutton (or Menuitem or
press shortcut) dozens of times before gthumb desides
to show me the image in fullscreen mode. That very
annoying.
Maybe the function expects something special to be
selected, but I dont know what.

I am using gthumb 2.1.2

Tobias