I usually work with 3-4 browser windows open, often 1-2 of those are "pop-ups" from other browser windows (for databases I work in), then Outlook (2011 Mac version). When working with emails I'm usually pulling information from browsers and copying/pasting into emails, or links, or something...some sort of information (I use the clipboard CONSTANTLY) and in Windows, a single click on the button for the window I want back into focus and I'm there. In OSX, hold option, click, hold, mouse up to selection click again...