Hi hay, always nice to hear from you.. even if you're not always carrying good news!!
I don't really (really!) have good suggestions for your case.. lots of people (hundreds to thousand est. users) are using FEEL both on XP and 7 with no notable graphics issues.. they've reported good working with almost any possible version of mame (even "heavily modded" ones), although I must admit I don't have enough users on groovy, which btw is quite "aggressive" in managing video modes.
I've been reported about some issues in resolution changes similar to yours only on some "weird" emulators (1-2 cases upon almost 100 tested systems) but the average user shouldn't care about them.
I'll need to make a full test session with groovy to work it out.. I'll let you know.
Anyway, in my and other users' tests, XP 32bit + Radeon + CRT emu drivers is still the best stack for arcade-cabs (or cab-like, as in your case
), even if I am currently looking for setting up a new PC with 7 (moving my cab to a "newer" PC - a luscious core2duo!!
), as it is very well supported by FEEL (I myself develop on it).
Win8 and 10 as well are, so they say (I don't use 'em).
Sticking to 7, be sure to use a MS "stock" installation (there's a lot of badly assembled install + crack ISO around on p2p sources), and don't forget to fully patch Windows first of all, otherwise you'll experience frequent explorer.exe crashes (sorry, it looks like FEEL's fault, but instead it's something in the stack 7->.net->xna, not really related to FEEL code). After a full win update you should be good to go with no more errors (this has been confirmed by a lot of users).
Even focus losses like yours, occasionally occurring (more upon FEEL in win autostart) have already been analyzed and managed in the past (in fact there's no more reports about them). But if you keep experiencing this I can possibly add some more accurate logic for re-gaining control after emu termination.
Let me know