I may be a little late to the game on this, but maybe as an alternative you could have the titlebar not show until an item in the folder portal has been selected. What's most distracting for me is that it pops up, sometimes only partially, going about my daily business. Better yet, maybe it would be possible to have the titlebar hidden on folder portals that have the option to "Allow navigation" disabled, or as a standalone option (that could potentially be set from folder portal to folder portal) to disable it for people who understand they will be losing the option to use the titlebar for navigation.