problem in Firefox, IE its ok

Suite and Optimus Suite 5
#1

Hi,
in file its print screen.
In Firefox on bottom sometimes is empty place. When I click for example Firebug, this empty place disappear.
In IE its ok.

I have version 2.5

#2

Are you sure that this place is part of the grid?
If issue still occurs - can you provide any kind of sample or demo link where it can be reconstructed.