I installed the official VirtualBox V 5.2.32 from the KDE repo and even install Oracle Extension pack 5.2.32r132073.
All works but my USB devices are still not recognized - I never got this working in Neon. What is wrong?

You have to install the following:
Virtual extension pack
gnome-system-Tools
Then do the following:
Go to Users and Groups
manage groups
vboxusers, and activate, or check the box for vboxusers
Restart the computer, and now you can see the USB under the devices!

Thx, in fact I forgot to add te user to the vboxusers group. It fixed the USB problem. Perfect!