I believe that's a feature, not a problem. Live chess is supposed to replicate as much as possible the rules of OTB tournament chess. Imagine if you started moving pieces around like that OTB; it wouldn't be tolerated, right? So why do you think you should be able to do it here?
EDIT: My bad, thought you were talking about live chess. Just use the analysis board to see what your move will look like.
Sorry it's not too clear but are you trying to put the piece back to the square it was on because you changed your mind? If so, I think you can drag the piece completely off the board and then let it go. It should bring the piece back to where it was before you clicked on it. That is how I do it, although I don't know if they changed that since it negates the touch move rule and actually allows you to choose another piece. I haven't played a game here in a while so things might have changed.
I assume you are talking about 'online chess'
If you want to see how the position looks like, you might want to use the analysis board (there is link 'Analyze' next to the game board)
If you made a move on the main board and you want to put the piece back, you can use the 'Cancel' button.
With regard to the (slightly superior tone) reply from BADDUGNO just bear in mind that during the years up to a few month ago when my friend and I played on-line chess with chess.com (we still do) we were able to move a piece back without having to go out of and into chess.com providing we kept the button pressed on the mouse so this useful feature was already available by chess.com and not something we dreamed up, moreover, how many times in domestic live chess games (I don't know about high class chess) do players move a piece and then, still keeping their finger on the piece, move it back to give more thought - but thank you for commenting on this. .
This is a problem experienced by myself and playing friend (using different computers) but as every chess.com player knows you often drag a piece to another space on the board, keeping finger on the mouse pressed, to see what the overall position looks like. You then release the mouse if you want the piece to stay there, however, if you want to drag the piece back again you do so, still by keeping the mouse pressed, however, in both our cases the piece simply boucnes back to where we have just moved it to to and in order to return the piece to its first position we have to log out completely and re boot in to chess.com. Has anyone else experienced this problem and is there a solution. Mike Haywood (mike6haywood)