A model can be displayed in up to four windows simultaneously. When two windows are displayed, they can be displayed tiled horizontally or vertically. A different view can be displayed in each window. Use the Options menu > Windows command at any time to specify the number of windows to be used.
As a shortcut to close a window, click on the X in the upper right-hand corner of the window. The remaining windows will automatically resize. This method cannot be used to close the last window.
A window is the "Active Window" when its title bar is highlighted. Only one window at a time can be active. Click in a window to make it active.