bar on bottom

how do i get rid of bottom bar that shows friends on line --live updates--share page--it interfers with display of time and rating--somtimes a arrow comes up but i can not figure out how to do it when i want to hide the bottom bar---help

I've been wondering the same thing.

go to My Home/Privacy settings: http://www.chess.com/home/privacy.html

there, find the CHAT BAR setting. You can choose "never show".

can take back mode be set up ,for when hand slips on mouse when moving a chess piece

For that you need to change from touch move to submit move in your online chess settings.  Takeback mode is for playing unrated instructional games, where you give your opponent a chance to takeback a move and replay it.