This is a very strange one. If you're running EpicTable in a non-maximized window, and you try to use controls on the Format tab (specifically X, Y, W(idth), H(eight), Fill Color, Fill Opacity, or Border Color, not only will the change not occur, but your window will be made taller. This happens until the window is (for reasons I don't understand) "tall enough" or until you maximize the window.
I've traced this back to an issue in the control library I'm using for the ribbon. It's quite old, and I'm using an entirely different one for EpicTable 2. Since EpicTable 2 will be a free upgrade, and I don't want to derail its development to fight a misbehaving control in an outdated library, I'm documenting this as a known issue and will make sure it's not present in EpicTable 2.
The easy workaround is to simply maximize your ET window, or possibly, simply make it taller. I apologize for the inconvenience on this one, but I think you'll get a much better result if I continue to push forward on ET2 than if I take time to fight this specific issue. Please let me know if it's causing undue pain.