Not an earth-shattering issue but why does the UI need to be so big? On 1024x600 screens It’s like Windows 8 apps all over again.
I’m using a 22 inch LCD monitor running 1920x1080, so I changed my resolution to 800x600 to see if I could understand your issue. And you are right! The GUI is huge and doesn’t upscale or downscale correctly with the resolution. With 800x600, the GUI is well outside of the screen. Funny, I guess, not really. Avast engineers must have hard-coded the GUI size?!?
We have huge LCD screens in our offices, that’s the problem ;-). To be serious, we know about the issue. Designers are finding a solution.