Move an Application Window From Off-screen Back to Your Main Desktop

  1. Right-click on the Windows taskbar and select Cascade windows from the pop-up menu.
  2. Hold down the Shift key, then right-click on the appropriate application icon in the Windows taskbar.
  3. On the resulting pop-up, select the Move option.
  4. Begin pressing the arrow keys on your keyboard to move the invisible window from off-screen to on-screen. Typically, you will use the left arrow to move the window from right to left.

References
https://support.ti.davidson.edu/hc/en-us/articles/115016089728-Move-an-Application-Window-From-Off-screen-Back-to-Your-Main-Desktop-Windows