menubar app behavior vs full screen app spaces (mac os 10.7/lion)

Question

When you have an app in fullscreen mode (in a fullscreen space) the menubar is hidden unless you "nudge" the top of the screen. However if you hit the spotlight hotkey the menubar politely shifts down into the screen with the spotlight search bar. Excellent.

I am migrating a statusbar/faceless application that I wish to have emulate this spotlight's menubar handling. Under snow leopard the app responds to a system hotkey by displaying a menu (it has a NSStatusBar item and I call popUpStatusItemMenu). Under Lion when the app is in fullscreen mode/space however, the menubar remains hidden for the fullscreen app (note however that the hot key IS bringing up the statusbar item and using the keyboard I can activate individual actions on the menu -- I just can't see the menu pop up).

To reiterate - anyone know how spotlight (under lion) displays the menubar in response to a hotkey? Or should I be asking when a better way to handle my UI would be under Lion?

thanks,

Answer 1

I feel reasonably certain that Spotlight is using private interfaces to change the presentation mode of the login session. You can change the presentation mode for an application using -[NSApplication setPresentationOptions:] (or the deprecated-but-still-available Carbon equivalent SetSystemUIMode()), but these explicitly only propagate to the login session from the “frontmost faceful application”.

I suggest filing a suggestion for an API to request that certain UI elements (menu bar, dock) are shown if they’re currently in autohide mode from the background.