Okay…, I installed version 7.8.0 so as to have the internal DebugView business.
I enabled DeBug logging and restarted digiKam.
I went straight to one of the problem tags that has been freezing digiKam every time I right-clicked it.
Completely expecting digiKam to crash as soon as I right-clicked the tag, I went ahead and right-clicked it — the little right-click menu opened and digiKam did not crash.
I clicked New Tag and no crash.
I clicked Properties and no crash.
I tested several more of my problem tags with the same results = no freez-up - no crash - everything worked as it should.
I disabled the DeBug feature and restarted digiKam again; I fully expected the problem to return now that DeBug was turned off — so far, so good; now all of the problem tags are working as they should with no crashes.
I don’t know how long this bit of good fortune will last and we may never know just what was causing the mysterious problem.
Will it have created a DeBug log file that will tell us anything helpful seeing as the program didn’t crash as expected ?