+++ This bug was initially created as a clone of Bug #752197 +++ All dialogs that currently appear as windows should be in-content (Google Chrome handles this very good). As dialogs that I can think of right now there are : -Exceptions, Fonts and languages in "content" preferences -"Cookies" and "clear recent history" in "privacy" -"Passwords" and "Exceptions" in "Security" -"Pair a device" and "Set up sync" in "Sync" -Various dialogs in "Advanced" -"Page info", "Page source", "Error console" and other devtools (in-content tab or sidebar) -"Print" Final result should be having no more separated windows in the browser.

Don't think we need to break this down, at least not in this iteration.