Now I am sure there is something going on, but it seems to happen
sporadically. As you can see in this image*, Tor is enabled after I
started IceCat right after I booted up my computer. The "Test if Tor is
enabled" link confirmed that, yes, Tor is enabled. IceCat doesn't seem
to properly detect if a private browsing window is open or not.
Sorry for my schizophrenic-seeming problem/no-problem emails.