When FKA is off, only textboxes and list controls should be in the focus loop. Right now, all form controls (popupmenus, checkboxes, buttons) etc always are.

Last I knew, FKA focus is respected in Fx (bug 187508, bug 242831, bug 277516) and is overridden in Camino (per pink, after trial run with FKA, "do the right thing, what the user wants; users won't know to change an obscure OS pref to change this"; bug 316339). It may have been backed out in Fx since I don't follow closely (I saw a lot of user complaints about the tabbing behavior being "broken" in 1.5), if it's not working there now. Or did you file this about something else?

I filed this because FKA was not respected in Camino. Then I noticed it worked in Firefox... and then I debugged for about ~6 hours before your comment. ;-( I guess if the mighty pink says so, we'll implement the pref in bug 277706.