> the main advantage is that you can see both source and compose at once without needed to switch back and forth. Until you click back on the Reference window

> the main advantage is that you can see both source and compose at once without needed to switch back and forth. Until you click back on the Reference window and your Compose window suddenly disappears into the z-order void of your windows manager. I find it much easier to flip between two tabs than two windows, especially with Chrome's excellent tab strip UX. I'm not interested in having to constantly move/resize windows to see both pages at once. (A decent focus-follows-mouse (no autoraise) solution for OS X would be nice as well!)