How about posting a screenshot?
Chessmaster 10 th green thing

Just a guess. A long time ago I had a chessmaster program and it would sometimes show a future position from a line it was calculating... I guess to sort of give a hint about what it was thinking. Is the board that pops up blank? Is it the current position or a future position or a random position?

Sounds like it doesn't happen very often, huh?
I couldn't get mine to do that. What mode are you in when it happens? Training games, rated games, or something else?
P.S. - The only tiny, green chessboard that I could produce occurs when I place the cursor on the border of the board. I've always ignored it though, as it doesn't seem to have any purpose.
I have just purchased a copy of CM 10. Kinda fun to play but no support as ubisoft no longher owns it. I have skimmed through the manual looking for the purpose of the little green chessboard that pops up when I put the cursur on some pieces. Can anyone tell me what it is?