If this is a glitch, it's not a glitch in the software, but in the player. Making a move, and then "midair" deciding not to. Touch a piece, and you have to move it. That's the rules of chess.
massive glitch

^ how are people making this so difficult to understand? are you guys trying to purposely confuse yourselves,or are you that incapable of understanding simple English?
He LET GO of the pawn in the 8th rank. That's it. The move is done. It's sealed. It didn't "glitch". He didn't just mouse over the promotion square and got stuck. He LITERALLY picked up the pawn,and put it there. Then he got a change of heart and got his panties in a bunch because he couldn't cancel the move.
Speaking of understanding simple English, you might want to look up the difference between literally and figuratively.
just for once, I whole heartly agreed with this statement above me (#54)