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I fell into this mode -- the error comes up with each restart.
Created attachment 14448 [details] The ide.log file
Reassign to core...
This looks like some netbeans installation problem, errors are signalizing mixture of classes probably from various versions. We can't do anything with this, I have just one advice - reinstall Netbeans into some clean separate place on disk and problem should go away. I'm passing to form guys just in case, because first error in from form module, but it's just coincidence I think.