Issue

You activate a command that normally opens a dialog window but that window is not visible anywhere on the screen. Perhaps you can see the window but it is mostly off the screen so that the dialog is not usable or you are unable to click to move it back into full view.

Cause

This issue can happen for a couple of reasons. The most common is if you have a secondary monitor that is sometimes connected and sometimes not. This is common for laptop users. If you disconnect the second monitor without first turning off the "extend desktop" setting in Windows or moving your dialog windows back to your main monitor first, windows that were on the second screen can become stuck in that position and then open off screen when using only a single monitor.

Solution

The following keyboard command can be used to move the window with your cursor keys or mouse so that you can move the off screen dialog window back into view.

ALT+SPACE+M , and then use your Arrow keys to move the window.

For Example: 
If I activate a command that normally should pop open a dialog window and I do not see the window or its in a position that will make it impossible to use, I would immediately press the ALT key on my Keyboard, and then the Spacebar, and then the letter M. I would then press one of the directional Arrow keys on the keyboard. At this point the dialog window should move in the direction I press on the arrow keys. The window then also becomes attached to the cursor so I can also move the mouse around a bit and see the window appear on the mouse cursor. I can then place the window where I like and press the Enter key or Left Click the mouse button.