file folders drag from file-roller to pcmanfm hangs external keyboard and mouse clicks

Hi, this bug is reproduceable on my Lenovo Y470 notebook. I am using this kernel with daily updates installed.

Linux alexia-pc 3.13.0-32-generic #57-Ubuntu SMP Tue Jul 15 03:51:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

I am using a external usb keyboard connected to the notebook.
My action is to select multiple files/folders from any zip file opened using Archive Manager (version 3.10.2.1), mouse drag the items out to a folder open under pcmanfm (version 1.2.0).

if i mouse release drop the items at the pcmanfm white zone then it works ok, but, if i mouse drag the items across the pcmanfm side-pan and then release the mouse at the white zone, the external keyboard and mouse click will locked up, and the mouse pointer will change to a closed fist with a chain, at this point sometime only the notebook keyboard is partially working. And there is no way for me to get out of this situation, sometime i need to force power button shutdown, other time i still can do normal shutdown from the notebook keyboard which only some keys are still working (up down left right arrow buttons are not working).

Please see if this is truely a bug that can be fixed in either in pcmanfm or/and file-roller or somewhere else.

Thank you.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: file-roller 3.10.2.1-0ubuntu4
ProcVersionSignature: Ubuntu 3.13.0-32.57-generic 3.13.11.4
Uname: Linux 3.13.0-32-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: amd64
CurrentDesktop: LXDE
Date: Tue Jul 22 23:11:25 2014
InstallationDate: Installed on 2014-05-04 (78 days ago)
InstallationMedia: Lubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2)
SourcePackage: file-roller
UpgradeStatus: No upgrade log present (probably fresh install)