Keyboard Shortcut Key: The Tilde (~) or Backquote (') Key usually found in the upper left corner of the keyboard under the Escape Key and next to the Number 1
You may also hear this as the Accent or Grave (`) Key
The Tilde (~) or Backquote (`) key maximizes any window that is highlighted and hides everything else.
If using Adobe After Effects or Premiere Pro or Audition to name a few, anytime you see the blue bounding box, hit the Tilde/Backquote Key and it will maximize that window and hide everything else.
I use this key all the time when editing video or organizing assets in Premiere. It's also very convenient when editing audio in Premiere and you want the waveform big to add keyframes.