This feature was delivered in HTML-Kit Tools update 20111216. To make sure that you have the latest additions, select "Help > Check for Updates" from the main menu.
Want more screen space and less distraction for editing those long files?
Full screen mode (F11 key) now gives you a fuller full screen view, filling up your display including the area used by the Windows Taskbar. The previous versions of HTML-Kit Tools didn't use the Windows Taskbar area. Pressing F11 again switches the editor back to the default view.
Here's a screenshot of the default view:
This is what you'll get when you enter the full screen mode: