Comment 24 for bug 230102

Created an attachment (id=313263)
nets out the same as original patch, but much saner

Realizing in discussion with gavin that the current flow sucked and should be simplified down to just this.

I might as well comment on the other patch I'm obsoleting. Gavin's alternate patch doesn't solve this well, because it does two key things wrong:

1) It allows a user to toggle a behaviour, without any UI to revert that behaviour. warnOnQuit has no UI, so users have no way of reverting the behaviour if they don't like it.

2) we continue to have a poorly inconsistent UI where we don't respect the global "warn me when closing multiple tabs" pref, as we did in Fx2. If I enable that warning, it doesn't happen on quit if session restore is enabled. That caused confusion here, and we should absolutely prevent that confusion and remove the regression in consistency.

This is a regression in terms of expected and predictable behaviour from Firefox 2, which is why its a blocker. This restores the Fx2 behaviour, except that we have a single dialog that has better behaviour than the old "prompt per window" behaviour. Its not perfect, and the warnOnQuit pref remains to enable the behaviour we had in the betas, but I am not going to ship what I believe is confusing and inconsistent UI, even if we got to the fix late in the development cycle. We ship betas to uncover user issues such as this, so I think any "we can't revert behaviour" argument is fundamentally flawed. If beltzner and I agree here, I think that's good enough cause to move forward.