Sometimes, when I exit a MAME game, mGalaxy doesn't respond to keystrokes. It happens like 1 in 10 times or so.
What happens is, that I can't move the cursor selecting games. I can open the "top 10" menu, but I can't move the cursor there either. I can also run games, even though the cursor isn't moving on screen, it seems to actually move in "background", so the game I start isn't necessarily the one highlighted.
When I open the filter keyboard, everything returns to normal.
I run Windows 7 64-bits and use an I-pac. I have customised the key mapping scheme for mGalaxy.
v5.0 also acted this way for me. MAME versions 0.149, 0.150 and now 0.152.