Drag and drop of pdf files not working on latest master in windows 10

[Siedlerchr]

JabRef version cb4b011

Steps to reproduce the behavior:

1. Try to drag and drop a file from the Windows explorer to the maintabe
2. It's not possible, you see a forbidden sign.

This was working before.

[Siedlerchr]

Seems to be fixed in the latest master with java 11 again.