-If the target window is not the root window, then this program
-will \fIalways\fP grab a desktop image. This means that if an
-image-manipulating xscreensaver mode is run in a normal window,
-it will always operate on a desktop image; it's only when it is
-run in \fI-root\fP mode (or when invoked by xscreensaver) that
-it will load image files or grab video.
+When grabbing desktop images, the \fIwindow\fP argument will be unmapped
+and have its contents modified, causing flicker. (This does not happen
+when loading image files or video frames.)