We are using docking frames for a while without any trouble.
But, since Oracle JRE 1.8_281 (and 291) something went wrong in focus manager (that my understand of the problem).
When file drag and drop is performed, the dockable application is freeze.
Stack exploration does not show somehting wrong : no thread blocked.
If a DefaultFocusRequest is trigger with a null component, very often, the Java application freeze.
I have spent severals days to resolve the problem without solution.
Can somebody could help me solving this trouble ?
Thanks for your help,