Some weeks ago Facebook introduced redesigned chat bar,many users disliked the new sidebar chat feature and some already started to protest it via facebook pages and group. I have collected some useful tricks to disable Facebook chat sidebar and revert it back to old facebook chat style.
You can use a Greasemonkey user-script & revert back to old chat interference. Chrome browser have built-in support for it but in firefox you need to have grease monkey addon installed [Download Greasemonkey for Mozilla Firefox over here.] .
Download user-script from here, for Chrome and firefox browser. After installing it will automatically revert back the Facebook chat to its old form disabling chat sidebar.
According to my observation , New Facebook chat is made to take advantage of wide-screen monitors and cover the white-space at side. You will see chat sidebar only if you have widescreen monitor (with 16:9 resolution). You won’t see chat sidebar if your display is in 4:3 ratio . So you can either change the resolution of your monitor to 4:3 ratio or zoom the Facebook page in your browser. Cltr+Scroll wheel can be used to zoom in or zoom out in most of the cases.
Get used to it! there is no way facebook is going to revert it back, even if people come down to road and protest it. Alternatively you can use Facebook messengers like pidgin , yahoo chat as they support facebook chat ports .