Comment 22 for bug 526453

What about changing the default engine every time the user changes what the topmost engine is in the search engine order? I think that's a fairly intuitive way for the user to say "I prefer engine foo over engine bar".

(I suggest this because someone on the mZ forum just posted about this problem and complained about how the default engine didn't change despite his re-arrangement of the search order.)

The upside to this is that this could be done with very minimal (read: zero) UI/string changes, is somewhat intuitive, and would (I think) be fairly low-risk for this late in the Fx3 game.