Text disappears when editing a Screenwriter production script

PROBLEM:  The issue is that typing in a LOCKED production script, the cursor will move as you type into the file, but the words won't show up. On checking the font color, it is black, but the words still do not show up.

You may also see: the moment you make a revision, the revision mark is drawn, however the entire text of the paragraph DISAPPEARS!

SOLUTION:

1. Use the FORMAT > Element Styles menu command.
2. Click on the "Locked Scripts" tab
3. You likely will find that the Right Margin for the Revision Mark may be up to 8.0 inches. This is supposed to be an INDENT from the RIGHT MARGIN, so the default is .5 (i.e., one HALF INCH from the right). You can't push the revision marks over to the left edge by indenting it by 8 INCHES.
4. Change the revision mark indent to a SMALL number (.05, or 1) and ALL should be PERFECT AGAIN!