while translating interface to my language I tested
Blender quite hard by doing things that normal user
wouldn't do, because they are kinda like useless. But
they reveal few tiny bugs.
Behold!


bug in appearance of the Gamma Slider (near post
process button):
when gamma enable/disable button (under 'fields'
button) change it's state, gamma slider
appear/disappear only when panel is updated (by
moving/zooming).