The Dock is one of those processes that restarts itself if it’s quit, so that’s all you should have to do.
In the confirmation dialog box that appears, click Quit. Open the Activity Monitor (it’s in the Utilities folder), select Dock in the list, and click the Quit Process button (or choose View > Quit Process). If this happens to you, the way to fix all of these problems is to restart the Dock. The keyboard shortcut to display the Dock wasn’t working either. Another thing that wasn’t working was moving the mouse to the edge of the display to make the hidden Dock appear. Today I tried to press the Command-Tab shortcut for the Application Switcher but nothing happened.
