I have the same problem. I have a 1920×1200 monitor. I’d like to set width to 1920, but there is the additional problem of a right-hand vertical scrollbar that appears whether or not it’s needed. Maybe it’s purpose is to provide consistency to the full-width header (rather than leaving a blank edge when the scrollbar is not needed), which would mean setting the header width at say 1900 (not sure how many pixels the scrollbar uses). All this is irrelevant, though, without the ability to control the header width. Oh, and I want to be able to set the header height as well. Such functionality should be in the free version. I have no idea if it’s in the premium version.