Leap 15.1 installed successfully on Virtual Box 6.0.10.
The Virtual Guest Additions ISO needed for full screen display on the host can be found here: http://download.virtualbox.org/virtualbox
VGA install instructions here: https://en.opensuse.org/VirtualBox.
Installed and configured Eclipse IDE on Leap15.1 in Virtualbox running on a Windows host.
Exported the OVA file to USB drive.
Imported OVA file as VM appliance on another Windows machine.
Booted Leap 15.1 successfully. Started Eclipse ID. No issues so far. The Leap15.1 VB combination is looking pretty bullet proof at the moment.
Just remember that VMs need a lot of memory. Recommend >= 12 gig for each VM instance to get decent raw metal desktop like performance.
Many thanks to the developers for making everything work so well.
I don’t know that 15.1 has ever had problems installing as a Virtualbox 6.0 Guest.
There were early problems installing Virtualbox 6.0 on a LEAP 15.1 HostOS, but those should be addressed by now (In other words, if you have a newly installed 15.1 from a DVD or NET, you must install system updates before installing Virtualbox 6.0).
TSU