After nearly two, exceedingly frustrating weeks working with inDesign support, today I finally found the solution. Would like to share in case anyone has a similar problem, which was to create a text frame in a master, create then 1 or more pages from that master, then try to type in that frame, which is dotted, not solid in the new page(s). I found that I could not type into a page created in this manner, i.e. FROM an existing master.
Earlier today, again after about 2 h. online with Adobe support, we finally hit on the correct workflow to achieve this:
–Create desired number of pages based on Master “(None)”;
–Create a new master (based, if desired, on an existing master);
–Add desired, new content to the new master just created;
–Pages | New Master | Apply master to pages | (indicate page number[s]).
New pages created in this manner will contain editable text frames.
All of this seems somewhat surprising to me, in that (a) text frames are so fundamental to written content, and (b) inDesign has been around for so long without having addressed this more explicitly, but there it is.