Vbox Manager can not see VM Started on a Console

[JSA]

Using
Manjaro Linux (Arch)
KDE5/Plasma5/SDDM
Virtualbox 5.1.2 from Manjaro packages


I start a VM was in a Terminal (Ctrl-Alt-F2 text only terminal).
Then, in a graphical KDE session I run the GUI Virtualbox Manager.
Manager shows my headless VM as NOT running. And vboxmanage list runningvms shows running in an xterm or Konsole shows no VMs running.

Reverse case also fails. Launch a VM from GUI Manager.
Then try vboxmanage list runningvms entered in terminal shows no VMs running.

Same User Login, I can see the VboxHeadless running in top.

Testing with others on the Manjaro forum indicates that this problem does not occur while running Lightdm + KDE (and other DMs and DEs).
It is confirmed to fail as above by others running KDE & SDDM. So right away, I tend to blame SDDM.

The VM is running in all cases, can be accessed by VNC, etc.

Question: What could SDDM be doing such that none of the tools can see VMs started outside their environment. What does vboxmanage need to have in order to find a running VM?

Note: I can start VMs via systemd, and get the same failure to connect. But the simplest case appeared to be starting from a non-graphical and a KDE session.

[JSA]

Note: This problem pesists with VirtualBox 5.1.4_OSE r110228

From an Xterm under KDE:

$ vboxmanage list runningvms
"WinSrv2008" {e5d25011-0e88-40ab-acfc-2936d4a56936}

From an ssh session to that same machine:
$ vboxmanage list runningvms
$

From Ctrl-alt-f2 console
$ vboxmanage list runningvms
$

All logged in with the same User ID that launched the VM.
Why do VMs launched under KDE5+SDDM not show running state?

[Perryg]

I suspect it is due to something in the manjaro build but you can post the guests log file to be sure.

[JSA]

I suspect it is due to something in the manjaro build but you can post the guests log file to be sure.

Nothing in the logs, I've looked.

I've traced this to sddm. Switching to LightDM this problem went away, and my machine runs the way I expect.
This has been confirmed by another user running XFCE desktop with sddm. I have no reason to go back to sddm,
as it offers nothing more than LightDM at the moment.
I've filed a bug report with sddm.
We will see what comes of that.