The frame outline help element is very important in the creation phase, and when switched on shows the true outline of each frame as a near-solid line. When switched off, the frame outlines (except those for the currently selected frame) disappear. (Note that if they are replaced by a dotted outline, you have Magnetic frame range switched to visible but with zero values for the snap-range.)
Since the frame outlines are often found disturbing when judging the appearance of a page, we recommend that you put this function on a macro so that you can quickly switch between displaying the frame outlines or hiding them.
