The "other" way to fix it is to edit the file...
/usr/share/applications/caja.desktop
and comment out as shown
#NoDisplay=true
#OnlyShowIn=MATE;
Caveat: This file is a "system-wide" file and may get overwritten on
updates.
This file affects all users
The previous "menulibre" solution is a per-user solution which adds a desktop
file within the user's
directory.
I opted for this fix. It was easy. It works.
Thank-you!