Unwanted Black White Swap

[Oliver Ruebenacker]

     Hello, dear friends,

  With F7 on my Dell Latitude D820 Laptop, I have been experiencing
this problem for a while, that often some but not all white surfaces
appear black and some but not all black surfaces appear white. It used
to be, that the problem, if it appeared started with the login dialog,
and would end when I restart, but since a little while it also happens
sometimes when I want to unlock the screen - and is usually solved
when I lock and unlock the screen again.

  Any idea? Thanks!

     Take care
     Oliver

-- 
Oliver Ruebenacker, Post-Doc Researcher
Theoretical Biological Physics and Soft Statistical Mechanics
Cell Biology at UConn Health Center and Physics at Harvard
http://people.deas.harvard.edu/~oliver/