I tried it also with computer with 1920 x 1200 resolution and text size 125%. Pictures are attached. If I change text size to 100% (this is too small), there are no problems.
@EV: Well, I write and test RUU on a 1920x1200 monitor with text size set to 100%. I personally think using the Display global text setting in Windows (to larger than 100%) is terrible because it scales EVERYTHING - including some things which I really don't need scaled - and so I lose precious screen real estate.
I think it's better to use: Control Panel\All Control Panel Items\Personalization\Window Color and Appearance\Advanced appearance settings...
and just change the font size of the particular text you want larger (message box text, title bar text, etc). Not only can you make more subtle changes to the size than you can from the Display settings applet, but changes you make happen instantly - without having to log off and on as you do with the global text settings. Anyway, just my two cents worth
But, in any case, I'll see if I can come up with a solution for this. It just means that the RUU display will have to be scaled when in the x1 setting - thus not matching precisely the Rigol's display.