I have quite a few of occurrences of this problem and can't figure it out. Last time I asked for help with a transparency issue it was addressed with some serious genius. Hoping for the same with this bug.
Either when I start access or hover over a few of my command buttons I get this. My properties are identical except the top margin. I have tried looking for a glow or shadow, but nothing is popping up. My database is 385mb in size running well within my allotted 6mb of RAM. I'm lost on this one.