How to prevent USB headset buttons to kill the mouse click handler?

I am running Xubuntu 14.04 on a Lenovo W530.

The other day we received brand new Plantronics Blackwire C420 headsets.

After a short while I realized that something was strange - and I nailed it down: the headset has 4 control buttons (volume up/down, mute, "phone"). When I press any of these buttons, the "mouse click handler" dies. This means: mouse clicks ... do not cause actions any more. If I unplug the headset; or close the application that is currently using the headset (like my SUT call window) everything goes back to normal.

I did some searching, found

https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/993655?comments=all

https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-evdev/+bug/1006156

The last link points to http://www.helplinux.ru/wiki/en:kb:ubuntu-plantronics

That page gives an instruction for 13.10 / 14.04.

So I ran

lsusb | grep -i plantronics Bus 001 Device 006: ID 047f:aa14 Plantronics, Inc.

Then I ran

sudo evtest (I selected the headset and pressed phone / volume up / volume down / mute on / mute off and got)

Event: time 1421919129.677039, type 4 (EV_MSC), code 4 (MSC_SCAN), value b0020
Event: time 1421919129.677039, type 1 (EV_KEY), code 256 (BTN_0), value 1
Event: time 1421919129.677039, -------------- SYN_REPORT ------------
Event: time 1421919132.913033, type 4 (EV_MSC), code 4 (MSC_SCAN), value ffa000b2
Event: time 1421919132.913033, type 1 (EV_KEY), code 261 (BTN_5), value 1
Event: time 1421919132.913033, type 1 (EV_KEY), code 261 (BTN_5), value 0
Event: time 1421919132.913033, type 4 (EV_MSC), code 4 (MSC_SCAN), value ffa000f8
Event: time 1421919132.913033, type 1 (EV_KEY), code 266 (?), value 0
Event: time 1421919132.913033, type 4 (EV_MSC), code 4 (MSC_SCAN), value ffa000f9
Event: time 1421919132.913033, type 1 (EV_KEY), code 267 (?), value 0
Event: time 1421919132.913033, -------------- SYN_REPORT ------------
Event: time 1421919133.959032, type 4 (EV_MSC), code 4 (MSC_SCAN), value ffa000b1
Event: time 1421919133.959032, type 1 (EV_KEY), code 260 (BTN_4), value 1
Event: time 1421919133.959032, type 1 (EV_KEY), code 260 (BTN_4), value 0
Event: time 1421919133.959032, -------------- SYN_REPORT ------------
Event: time 1421919135.896964, type 4 (EV_MSC), code 4 (MSC_SCAN), value b002f
Event: time 1421919135.896964, type 1 (EV_KEY), code 257 (BTN_1), value 1
Event: time 1421919135.896964, -------------- SYN_REPORT ------------
Event: time 1421919139.744963, type 4 (EV_MSC), code 4 (MSC_SCAN), value b002f
Event: time 1421919139.744963, type 1 (EV_KEY), code 257 (BTN_1), value 0
Event: time 1421919139.744963, -------------- SYN_REPORT ------------

Then I followed the instruction from the Russian page and created

cat /etc/udev/rules.d/49-plantronics.rules

ACTION!="add|change", GOTO="xorg_plantronics_end"
KERNEL!="event*", GOTO="xorg_plantronics_end"

SUBSYSTEMS=="usb", ENV{ID_BUS}=="", IMPORT{builtin}="usb_id"

ENV{ID_VENDOR_ID}=="047f", ENV{ID_MODEL_ID}=="aa14", ENV{ID_INPUT_KEY}="1", ENV{ID_INPUT_KEYBOARD}="1"

Plus:

cat /etc/udev/hwdb.d/50-keyboard.hwdb

keyboard:usb:v047FpAA14*
KEYBOARD_KEY_ffa000b1=volumeup
KEYBOARD_KEY_ffa000b2=volumedown
KEYBOARD_KEY_b002f=micmute
KEYBOARD_KEY_b0020=phone

Finally I ran ... sudo udevadm hwdb --update ; sudo udevadm control --reload ... and I also rebooted.

Long story short: it doesn't help. When pressing any of the buttons, the mouse click handler still goes away. Interestingly enough, coworker is running same hardware with Gnome3 ... and he doesn't have this problem ;-(

Any thoughts, ideas, suggestions are welcome (expect "use Gnome3 instead of xubuntu"). For example I am wondering if there any log files that would tell me if these udef control files have any effect, or are malformed, ...