I've had the u2711 monitor up for a few days.  Somehow today I managed to lock the front panel controls (a little padlock appears when I press the one just above the power button).  The user manual (such as it is) says there's also anOnScreenDisplay menu but I don't see how to get to it (I certainly don't see the icon the manual says to touch).  Rebooting the computer certainly has no effect.  How can I unlock the front panel? 

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