Kurt,
I followed your advice about the QXP preference file, but QXP still did not recognize Futura if FontExplorerX Pro added it back as an active font.
After moving all of the fonts from /Library/Fonts to a folder on a partition, I created a set of the fonts removed from /Library/Fonts in FontExplorerX Pro [FEXP] and activated that set.
Based on some preliminary tests they all seemed to be available to as many Apple applications that I had time to test. I tried to add Futura to that set, but while it was available inconsistently to applications it was not available in QXP, which is of immediate concern. Many of the other issues I mentioned early in the thread seem to be resolved.
I then manually added all of the Futura Family of fonts to /Library/Fonts, and they instantly became available in all applications that I was able to test, but most importantly they were available in QXP.
Interestingly, the number of fonts available in any particular application was different depending on what application was being used. I believe that Corel's Painter made the most number of fonts available.
Just thinking about all this makes my head hurt. Clearly there is an issue that remains, but I'm at a loss as to how to troubleshoot any further. What is happening seems to happen in spite of font management by FEXP; QXP does not behave the same as some other applications in regard to font management; Painter seems to have every font activated always available, but I have not tested whether FEXP can activate or deactivate fonts that are available in Painter.
The manually added Futura fonts are available in QXP, Photoshop, Painter and Illustrator.
At this time I don't know where to go; the combinations and possible permutations of those combinations have just gotten me confused. I'm sure the issue is not systematically resolved across all applications, or that on El Capitan FEXP is able to properly manage fonts system wide for all applications, or that QXP properly manages fonts in conjunction with FEXP.
At this time the anomalies with my Apple applications seem to be resolved and the Futura Family of fonts is now available in all the applications I was able to test.
Kurt, I thank you for your great advice, and thoughtful help. I would like to get this straight, though, and perhaps we could work on these issues off of the forum.
Please let me know if this is something we could do.
To everyone else who assisted in this issue, Thank you!
Vincent