Here’s a quick tip for you Mac OS X users out there: you can move any window behind the currently active window (also known as the window that has “focus”) without activating it/bringing it to the front.

This one’s real simple: hold down the Command (Apple) key, and then click on the background window’s title bar area (as you normally would) and voilà – you’re moving the window in the background. You can even grab the scroll bar and move it if you have access to it.

This is super handy for those times when you may be using another image as a reference, or you have a text document or email message with instructions you need to refer to, but it’s obscured by the frontmost window. Of course, you’ll need to be able to click on it so if the window is totally obscured by the frontmost window, you’re out of luck. This trick is more for repositioning a window you can see.

This is a real productivity booster for those of us with a dual-monitor setup (dual monitors are set up so that both monitors act as one giant desktop. It’s awesome.). I constantly use reference images opened in Preview, and sometimes the palettes cover up areas where I need to inspect the image.