Update - the day before I was due to replace the combo switch (turn signals & headlight switch), the symptoms changed.
Now, if you the lights are on and the engine is running, and you turn off the engine (but not the lights) with the key - the engine actually stops running. That is positive, except I have no idea why it changed.
Also, now, when you have the key in the on position, engine not started, lights set to off, the parking lights/dash lights no longer turn on. Again, a positive thing, but without any good reason as to why this changed.
The new symptom is that if you press on the brake pedal - even with the engine off and the key out - the parking lights and dash lights will go on, until you release the pedal. Obviously the parking light wires are somehow crossed with the brake light wires - the tricky part is finding out where. Nothing looks obviously wrong.
oh, I did swap out the combo switch, and it doesn't seem to have had an effect. It was an easy swap; it took 5 minutes.