Unity crash when trying to "unlock from launcher" a disk drive icon

After the latest updates (proposed repositories enabled), I noticed that when I try to "unlock from launcher" a disk drive icon, unity crashes.

Fortunately, it restores itself quite quickly.

Another behaviour, if it's not crash, is to do nothing. It does not unlock/remove the launcher icon at all.

I was able to screen-recording the problem

https://www.youtube.com/watch?v=YvK3kppx1rg

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: unity 7.3.2+15.10.20150825-0ubuntu1
ProcVersionSignature: Ubuntu 4.2.0-7.7-generic 4.2.0
Uname: Linux 4.2.0-7-generic x86_64
NonfreeKernelModules: nvidia
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 355.11 Wed Aug 26 16:35:41 PDT 2015
 GCC version: gcc version 5.2.1 20150903 (Ubuntu 5.2.1-16ubuntu1)
ApportVersion: 2.18-0ubuntu9
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CurrentDesktop: Unity
Date: Fri Sep 4 22:07:33 2015
DistUpgraded: Fresh install
DistroCodename: wily
DistroVariant: ubuntu
DkmsStatus:
 bbswitch, 0.7, 4.1.6-999-bfq, x86_64: installed
 bbswitch, 0.7, 4.2.0-7-generic, x86_64: installed
 nvidia-355, 355.11, 4.1.6-999-bfq, x86_64: installed
 nvidia-355, 355.11, 4.2.0-7-generic, x86_64: installed
GraphicsCard: NVIDIA Corporation GF108 [GeForce GT 430] [10de:0de1] (rev a1) (prog-if 00 [VGA controller])
InstallationDate: Installed on 2014-10-24 (315 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
MachineType: MSI MS-7623
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-7-generic root=UUID=170bb898-7aa9-4678-8e80-58a445647f93 ro
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/28/2011
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: V17.10
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: 880GMA-E45 (MS-7623)
dmi.board.vendor: MSI
dmi.board.version: 3.0
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: MSI
dmi.chassis.version: 3.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrV17.10:bd02/28/2011:svnMSI:pnMS-7623:pvr3.0:rvnMSI:rn880GMA-E45(MS-7623):rvr3.0:cvnMSI:ct3:cvr3.0:
dmi.product.name: MS-7623
dmi.product.version: 3.0
dmi.sys.vendor: MSI
version.compiz: compiz 1:0.9.12.1+15.10.20150805-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.64-1
version.libgl1-mesa-dri: libgl1-mesa-dri 10.6.3-1ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.6.3-1ubuntu1
version.nvidia-graphics-drivers: nvidia-graphics-drivers N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.17.2-1ubuntu5
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.2-1ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.5.0+git20150819-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20150808-0ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu3
xserver.bootTime: Fri Sep 4 20:01:51 2015
xserver.configfile: default
xserver.errors: open /dev/fb0: No such file or directory
xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.17.2-1ubuntu5