Usually I use the middle click option to get one window from monitor to the other monitor.
However with Firefox 4, the top of the window does not react to the middle click. However when "menu bar" is added to Firefox 4 it does allow middle click to work correctly.
Is it possible to not use the "menu bar" within Firefox 4 and still use the nice "middle click functionality?
Unfortunately Firefox doesn't report the correct values when testing to see if the middle-click takes place in the titlebar. However, starting with Beta 6 (currently available for download) you can middle-click on the min/max/close buttons to move the window. It's not perfect, but it's the best that can be done with Firefox 4's new custom titlebar.