To change the size, background color, or appearance of a window (title bar or not, close box or not, etc.), bring the window you want to edit to the front and then choose "Edit Current Window" on the Interface menu.
During authoring, you can hide and show windows using the "Layer Controller", available from the Interface menu. The window names on the controller are also buttons that can be used to edit the window's characteristics. Next to the window's name is a twistdown which if you open up will show you all of the layers on that window and whether they are currently showing or hidden.