I bit the bullet and bought a current license for Xojo.
Using Xojo2015r3.1:
- the HTMLviewer issue has resolved itself
- the Console now gets System.DebugLog messages (previously there were no line item entries beyond what I had quoted)
Despite the minor bugs and slight learning curve with the new IDE, it’s nice to have everything working as I’ve coded it. Bottom line if anyone encounters buggy HTMLviewer issues in the future… updating Xojo version resolved it for me.
Thanks to all, especially @Michel Bujardet, for your troubleshooting attempts.