Error in loading component: [JFrame]->Panel - Java NetBeans

Question

So its been a while since I last touched the GUI for this application. Today I tried to open the main form and got this error message:

Note everything compiles/runs perfectly, I get no errors whatsoever.

Answer 1

It might be because you used to have a custom GUI window/panel/component and you modified that class. Now the IDE does not recognize it anymore, so just press "Not editable" button when NetBeans Shows you the dialog, then perform a "Clean and Build" (the broom and hammer icon). After build completes close and reopen the IDE. It worked form me.

Answer 2

It an error that append sometimes when you switch from a version to an other. I get the same issue, I got the message but all run well.

If you want more informations about the problem encoutered, go in :

(In the menu bar) View -> IDE Log

here you should see the details of the error when you get this Warning window.