Each window that is open will have two buttons in the top right-hand corner:
The options available are to minimise the window (>>) or to close it completely (X). Once a windows has been minimised it remain available as a tab at the side of the Maltego client.
Each of the minimized window has a single button to maximize the window again.
While the window is still minimized, if you hover over one of the window tabs, the window will open as seen below. The window will minimize again when you move the mouse away from the window.
Clicking on the window tab will open the window until it is de-selected again by clicking elsewhere in the Maltego client.
The solid dot button () in the top left-hand corner of the window will pin the window back into place so that it stays there permanently.
The windows can also be dragged around to snap into place in different configurations. It is all up to you to decide how you want to setup your working and of course the amount of screen real estate available.