Has anyone seen a patch/plugin to compose in a new window?

I use roundcube with prism as my only email app (I'm currently testing a small plugin I wrote specifically for prism that pops up notifications on new email and closes the window on logout and working on a mailto: wrapper program), but the point is I quite often find myself replying to one message but need information from multiple messages so want the compose in a new window. In firefox I could right click and 'Open in New Window' but this isn't available under prism.

I'm currently wandering through the available hooks to determine where and how I'd have to hook in to do this myself, but thought I'd check to see if anyone had already seen it before doing the work (A search in the forums found an old request for this feature, but no answers)