There are several ways to fix this without needing to be aware of the window's off screen position.

  - From the keyboard WIN+{Left|Right} resizes and pins the window to the side of the screen
  - From the keyboard WIN+Up to maximize the window (or right click on the task bar and select maximize.  Now, drag the title bar from the top and the window will unpin from the screen and move with the mouse
  - Right click on the task bar and choose any of the windows arrangement options (Stack, tile, cascade)