Chrome javascript pop up window has a wrong dimension

Question

I'm trying to open up a new window for a chat room on our site. I have the chat room's dimension set to 750px x 590px. This is the link I have to open up the javascript pop up.

<a href="javascript:void(0)" onclick="window.open('http://gamersunite.coolchaser.com/message/gu_chat','gu_chat','width=750,height=590')"&gt;open chat window</a>

All of the browsers look fine even on IE (screenshot http://grab.by/5qEj) but Chrome opens a window that is a little smaller which causes the scrollbar to appear (screenshot http://grab.by/5qEg)

I googled for a long time but am unable to find the solution. I would greatly appreciate any suggestions.