virtualbox interferes with shutdown,restart or logout

[Kev Bowring]

With a vm running a guest in virtualbox.

Trying to either shutdown,restart or logout the host machine halts, vbox close machine dialogue opens.

Need to reopen the shutdown dialogue after vbox has been dealt with.

At least one other application had closed during the failed shutdown/restart. (Notably one on the same workspace as vbox, leaving one open and vbox asking for decision)

Behaviour noted when using either PPA version or default package.

Locking screen works.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: xfce4-power-manager 1.4.4-4ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-14.16-generic 4.2.2
Uname: Linux 4.2.0-14-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.19-0ubuntu1
Architecture: amd64
CurrentDesktop: XFCE
Date: Thu Oct 8 16:12:18 2015
InstallationDate: Installed on 2015-10-01 (6 days ago)
InstallationMedia: Xubuntu 15.10 "Wily Werewolf" - Alpha amd64 (20151001)
SourcePackage: xfce4-power-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[Kev Bowring (flocculant)]

Installed 15.04 Xubuntu - same behaviour noted.

(Not seen in Ubuntu)