Display Setting is not showing

For show unity setting

$unity-control-center

Setting in command line
$xrandr
...
DVI-I-2 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200     59.95*+
   1600x1200     60.00 
   1280x1024     75.02    60.02 
   1280x960      60.00 
   1152x864      75.00 
   1024x768      75.03    70.07    60.00 
   800x600       75.00    72.19    60.32    56.25 
   640x480       75.00    72.81    59.94 
...
$xrandr --output DVI-I-2 1600x1200 #for choice
$xrandr --fb 1152x768 #another way
For problems in aspect ratio (wide mode), for us the better choice is:
$xrandr --output DVI-I-2 --scale 1.0x0.85


Other alternative is related to create new entry, using next commands

$cvt 1600 1200 60
 # 1600x1200 59.87 Hz (CVT 1.92M3) hsync: 74.54 kHz; pclk: 161.00 MHz
Modeline "1600x1200_60.00"  161.00  1600 1712 1880 2160  1200 1203 1207 1245 -hsync +vsync

$xrand --newmode "1600x1200_60.00"  161.00  1600 1712 1880 2160  1200 1203 1207 1245 -hsync +vsync

$xrand --addmode "1600x1200_60.00"  #but doesn't works for us