I have the exact same problem.
And when I set to open in an iframe is stays “greyed out”.
Anyone got any suggestions?
I have a problem with this function causing all of my other functions in the main plugin file to be seen as declared thus giving “Fatal error: Cannot redeclare”.
I am guessing that by saying __FILE__ it loads the file and suddenly it’s been loaded twice.
Any ideas!? I have searched the forums but everyone seems to talk about global scope which I don’t see has anything to do with it.
I have exactly the same problem!
Thought it might be to do with permissions but still haven’t found a solution.