If multiple Display windows are ``included'' (see Section 2.3.4), synchronized picking is enabled. If you have two (or more) images which at least partially overlap in world coordinate (RA-DEC-VELO) space, including them synchronizes them for the purpose of interactive display of intensities, profiles and/or for region selection at the same world coordinates. For example, suppose you have CO and HCN maps of the same object (they need not be the same size in either RA-DEC-VELO or pixels, since the synchronization is based on world coordinates and not pixel coordinates). By ``including'' both maps, when you display intensity values by using the mouse to point at one image, the intensity value of the other image at the same world coordinate will be displayed. When you display CO line profiles by interactively roaming the mouse pointer around the CO image, the HCN line profile at the same spatial position will also be displayed. If you do a subregion selection on the CO image, the same subregion will be selected on the HCN image. When the Track 3D toggle (in the Include submenu of the Options menu of the Display window) is on, included windows will change the displayed slice if their Z axis matches the X or Y axis of the window with the cursor.