Why can´t i see the display where the iMultiviewer window is located ?

If you select the display, where the iMultiviewer is located, you'll see this symbol. Imagine to capture a screen with a camera and this screen shows the output of this camera - the picture will be repeated over and over again. This is what would happen, if you display the screen, where the iMultiviewer window is located. Doesn't make really sense, hm?