One of the most intriguing features of components is the fact that you can assign an interactive Flash movie to play inside, and effectively replace, the Component Parameters panel (or the Properties panel’s Parameters tab). The process involves first building a Flash movie, exporting it as an .swf, and then pointing to the .swf through the Component Definition dialog box. You’ll have two files: an .fla file with the master component in a Library and an .swf that plays inside the Component Parameters panel. The .swf is called a custom UI, and its filename is specified in the Custom UI field (see Figure 15.11).