A way to recover the toolbars from popup windows that hide it

[pile0...@gmail.com]

I think it would be good to have a way to get the browser UI back
inside a popup window that hides them. Perhaps there could be a thin
gray bar with an arrow (something like that) at the top that you can
click and show the toolbars. Or an about:config option,
browser.popups.toolbarHidingMode, to switch between 3 modes:

1 - allow toolbar hiding without the gray bar
2 - allow hiding with the gray bar
3 - and disallow toolbar hiding by popups at all.

It should be set to 2 by default.