Currently Being ModeratedMar 2, 2013 11:25 AM (in response to jeanphicrosoft)
Partial solution ...
I'm using my Mac at work, and I have a second session, only dedicated for that (non admin ...)
I discovered last Friday during a presentation that the icon was available in the menu bar in this session.
Currently Being ModeratedMar 2, 2013 11:21 PM (in response to jeanphicrosoft)
In the Finder hold the Option key and choose "Library" from the Go menu. Then go to the Preferences folder in here and remove the file called "com.apple.systemuiserver.plist" and then log out and back in to your account. Then try setting the Displays menu extra to show in the menu.
Does the menu show up for other user accounts (create a fresh one to test this out if you don't have one)?
Currently Being ModeratedMar 2, 2013 11:22 PM (in response to jeanphicrosoft)
You have a Mac compatible with AirPlay Mirroring. See > http://support.apple.com/kb/HT5404
That's the icon you are seeing on the menu bar, and it's to mirror the computer to an Apple TV, not to an external display. Apple has removed the Displays menu in OS X Mountain Lion, so you need a third-party app to make it appear again, as Display Menu > https://itunes.apple.com/us/app/display-menu/id549083868?mt=12
Currently Being ModeratedMar 2, 2013 11:40 PM (in response to mende1)
Maybe compatible, but (don't be angry ...) this is not the question, and i'm not convinced with your second comment because this icon exists in ML, and it can work, to manage also external display.
At work, there is no Apple TV, nore any other airplay compatible stuff : ML is not only dedicated to be used at home.
What I'm interested for, is to use the original program provided by OSX, discover where is the issue in the principal session, because it can work, as expected.
For me, this is a bug, not a restriction.
Currently Being ModeratedMar 2, 2013 11:53 PM (in response to Topher Kessler)
Interresting again !
I have done what you've suggested.
It doesn't work !
BUT i'm at home, and i'm trying with my videoproj, not the screen we have at work (a NEC plasma monitor) : it doens't work in any of my sessions.