Bug in drag and drop

If move a piece slowly and wrongfully you put it in an intermediate cell, system will accept it as two continous seprate moves and you will not be able to do the next move!

I think, it should block the second move and just move back the piece to intermediate cell. It may happen specially while you are playing with a notebook touchpad.

I'm sorry, I'm not sure what you're saying? Can you maybe take a screenshot and show us?

Assuming your talking about Live Chess the behaviour you're describing sounds like pre-moves.  Either turn them off under settings or right click to cancel the original pre-move before entering another.

My question is why system does not block such a mistaken two successive moves. How I should be able to move a piece two times before the other side guy do any thing!

This bug may happen because of lag of network! I am not a network programmer ;)

The system allows you to submit multiple, sequential pre-moves.  Assuming I've understood your problem correctly It's actually a feature, not a bug.

My suggestion is that if you want to use pre-moves, try right clicking to cancel them when this occurs.  If you do not, turn them off altogether.

This is a wonderful site - nice history. Instead of screenshot, just look at steps 24 and 25 for white(me) in the following game:

http://www.chess.com/livechess/game.html?id=2317671

Was move 24 a pre-move?  If so right clicking would have cancelled it as long as you managed to do so before your oponent moved.  If not there's really not a bug here, just a mouse-slip.