[texworks] Plane 1 characters not visible in TeXworks

[David J. Perry]

This is a followup to my post from yesterday.  Things get weirder.

Earlier tonight I opened TexWorks to do some more work on the file I 
used yesterday.  This time I saw empty rectangles where the Old Italic 
characters are.  This is better than nothing, although I'm still not 
sure why the characters won't display.

A few minutes ago I wanted to make a last-minute correction and opened 
the file again.  Same computer, same fonts, same everything as earlier 
today, but now we are back to total blanks.  ???