FileChooser - cannot drag-and-drop files from the Finder (macOS)

[Sciss]

This works nicely on Linux, and I use it frequently: You have an open JFileChooser, and from the desktop manager (e.g. Nautilus on Linux or Finder on Mac), you drag and drop a file or directory onto the file chooser to select it. Somehow the DnD is rejected on macOS (tested with JDK 8 and JDK 11 on macOS 10.13.6). I have other places in my app, where I use this drag-and-drop functionality, and it does work on macOS, so I guess it is a file-chooser specific issue (perhaps single file versus file-list).

[mgarin]

Probably related to: #423
Shortly, there was a bug in JDK8: https://bugs.openjdk.java.net/browse/JDK-8160941

Although it is marked as fixed in JDK 8 update 152, so it shouldn't have appeared on any JDK 11 for you (potentially). It will require some testing to see what's happenening and if it is related. I'll put this to a few other Mac OS X issues I'm going to focus on shortly after the performance improvements I'm working on right now.