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This may or may not get fixed in the future, but it's not going to be specifically addressed, since fixing it for one resolution tends to break it for others.

I really don't think there's a way to fix this. As far as I can tell I have SBarInfo using floating point coordinates whenever they matter (DSBarInfo::DrawGraphic), but as soon as you fix one precision error another comes up.

I've noticed a minor rendering bug with regards to the Hexen statusbar.
I've used a self-compiled binary using the SVN version R3516. (ZDoom)

To emulate the bug, just fire-up Hexen, start a new game with any class (I've used the barbarian).
Once you're in the game, press ESC to get to the menu, wait a second or two, and press ESC again to get rid of the menu.
Now you'll notice a small blue line running across the top of the statusbar.

It seems as if the 3D viewport should be added another pixel or two vertically, as the area where the blue line appears is an area not being drawn to be either the 3D viewport or the statusbar, which is where the blue color of the menu accummulates.
I'm not sure how the viewport sizes are calculated, but I'm getting this when running on my native 1920x1080 resolution.