I just got dual monitors and I want to restrict my Wacom tablet to draw on only one. Unfortunately, xsetwacom doesn't seem to recognize the DVI inputs--even though they're listed in xrandr plain as day. Any ideas? 

Here's my console output: 

```
andrewcarr@andrewcarr-desktop:~$ xrandr
Screen 0: minimum 8 x 8, current 3200 x 900, maximum 16384 x 16384
DVI-I-0 connected primary 1600x900+1600+0 (normal left inverted right x axis y axis) 443mm x 249mm
   1600x900      60.00*+
   1440x900      59.89  
   1280x1024     60.02  
   1280x720      60.00  
   1024x768      60.00  
   800x600       60.32  
   640x480       59.94  
DVI-I-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DVI-D-0 connected 1600x900+0+0 (normal left inverted right x axis y axis) 443mm x 249mm
   1600x900      60.00*+
   1440x900      59.89  
   1280x1024     60.02  
   1280x720      60.00  
   1024x768      60.00  
   800x600       60.32  
   640x480       59.94  
 andrewcarr@andrewcarr-desktop:~$ xsetwacom set "Wacom Intuos PT M Pen stylus" MapToOutput DVI-I-0
Unable to find an output 'DVI-I-0'.

```