Pressure sensitivity doesn't work in Inkscape (0.91 @ Ubuntu 15.10 repository)

Pressure sensitivity doesn't work in Inkscape (0.91 @ Ubuntu 15.10 repository)

Software:
Ubuntu 15.10 64bit
Inkscape 0.91

Hardware:
Wacom Cintiq 21UX

[How to duplicate]
[1] Installed Inkscape 0.91 from Ubuntu 15.10 official repository.
[2] Inscape->Edit->Input Devices, from Input devices list, find the following Wacom device, and change Mode from "Disable" to "Screen":
   Wacom Cintiq 21UX P = "Screen"
            |_Wacom Cintiq 21UX Pad pad = "Screen"
            |_Wacom Cintiq 21UX Pad stylus = "Screen"
            |_Wacom Cintiq 21UX Pad eraser = "Screen"
[3] Click "Save", and restart Inkscape, also restart Ubuntu

[What should happen]
Inkscape should recognize pressure sensitivity

[What happened instead]
Still no pressure sensitivity.
If I go back to Inscape->Edit->Input Devices, I found the following setting: the Wacom Cintiq parent not is disabled again. I attached a screen copy for this setting.
   Wacom Cintiq 21UX P = "Disabled"
            |_Wacom Cintiq 21UX Pad pad = "Screen"
            |_Wacom Cintiq 21UX Pad stylus = "Screen"
            |_Wacom Cintiq 21UX Pad eraser = "Screen"

NOTE:
From the same computer, no such issue with GIMP. Pressure sensitivity works fine in GIMP.