If you use multiple monitors, you've probably run into the problem where you disconnect from the secondary monitor without first moving the windows in the secondary monitor onto your main window. When you do this, the windows that were in the secondary monitor are then unreachable or are shown in the main window, but you can't grab the navigation bar to move them into the main window. If that happens to you, here's how to get move those windows back onto the screen of your main monitor.

Hold down the Alt key and press Tab until the window you want to move has the focus (Alt + Tab tabs the focus through your windows). Once it has the focus right-click the icon for that window in the task bar and select "Move". You can then use the arrow keys on your keyboard to adjust the location of the window that is off the screen so that it gets moved back onto your main screen.