I'd be pretty afraid of touching that XBL stuff, myself... It's very fragile, and not well tested. It's buggy in various ways, but we don't want to change those ways if we can avoid it, this late in the game.
It does seem like this would be a problem for anything in XUL that loads from content, though. Or for any XUL that uses an inline script. And I'm sure the lack of notifications in XUL also causes bugs in content lists, and so forth.
So really, we just need to fix XUL to notify properly... That's clearly not 1.9-scope, though.
I'd be pretty afraid of touching that XBL stuff, myself... It's very fragile, and not well tested. It's buggy in various ways, but we don't want to change those ways if we can avoid it, this late in the game.
It does seem like this would be a problem for anything in XUL that loads from content, though. Or for any XUL that uses an inline script. And I'm sure the lack of notifications in XUL also causes bugs in content lists, and so forth.
So really, we just need to fix XUL to notify properly... That's clearly not 1.9-scope, though.