What if I want to see the main menu and do something with my window?
No big deal, simply press ALT and the menu shows up.

Selecting the "Switch Windows" option lists the currently open windows, 1 up to 9, and you can click on them to bring them forward, and switch input to them.

Close window closes the active program window, obviously.

It also asks you to confirm, which is a good thing if you have unsaved work that you want to keep.

Rearrange allows you to do just that: rearrange your program windows. This can be helpful with the fullscreen apps that are covering up what you want to see underneath them.
Of course, you have to know what all the positions mean.

It also offers a crude control panel for controlling basic things about Desqview.