Not ugly export ?

A resolution change wouldn't cause this type of distortion.

It does. To run Windows 8 on my Netbook, I had to set a resolution, that is not native to my screen size (it has a weird size). After setting the resolution to a value the system supports, the desktop became stretched to fit the screen. While working in normal programs, everything looks fine, but in my installed browsers, images and text looks not weel.

I have tested the .capx on two systems, neither using stretched desktops. One machine had the glitch, and the other machine displayed it correctly.

That means it's a graphics driver bug. Even if your drivers are absolutely latest and up to date (as they were on my two machines), they can still be buggy! Graphics drivers are terrible and a huge let down on the technology as a whole. We've blogged about this a lot, for example here. Let your graphics card maker know they're doing a poor job. Unfortunately there's very little we can do to fix it - if we change how games are rendered, we risk breaking it for machines which do display properly.

The machine showing the glitch had an Intel HD graphics 3000 chip. Maybe this is an issue with Intel chips only?

It does. To run Windows 8 on my Netbook, I had to set a resolution, that is not native to my screen size (it has a weird size). After setting the resolution to a value the system supports, the desktop became stretched to fit the screen. While working in normal programs, everything looks fine, but in my installed browsers, images and text looks not weel.

Well, I can't speak about Win 8 since I don't have it (and most likely never will).

Intel chip... Mmmm, I'll check my laptop when I'll get home to see if it's an Intel too.

EDIT : Yes Ashley, on my laptop I've a Intel(R) HD Graphic 4000