Cascade
Arrange windows so they overlap.

Tile Horizontally
Arrange windows as horizontal, non-overlapping tiles.

Tile Vertically
Arrange windows as vertical, non-overlapping tiles.

Arrange Icons
Arrange minimized windows as non-overlapping title bars at bottom of main frame.

Next
Activate the next window by moving the current active window on the pile at the last position so the second window will become the active one.

Previous
Activate the previous window by moving the the last window on the pile at the first position and make it the active one.

Close
Close the active display window of a project.  If it is the last display window of that project, it also closes the project itself.

Close All
Close all the display windows of all the projects.  Same as using the menu [File --> Close] for each opened project.