What if, however, you want to move the file associated with a window that is in the background? Command-clicking on the title will bring up the background window's file hierarchy, thus spoiling your attempt to drag the file in the background. You can work around this by using Command-Shift-Click instead of just Command-Click. Hold for a second, and then drag to move the file of window in the background. The Shift key avoids bringing up the pop-up menu and lets you drag the file!
This is very handy for dragging BBEdit windows into the developer tool FileMerge, for example, without playing window and application switching games.

