16.04 - xrandr increases virtual size for display 1 when adding display 2 - Ask Ubuntu

i tried customize xrandr bit when add second screen, first screen's virtual size gets increased size of 2 displays!

when move cursor second display, first 1 slides part of screen if small window on bigger screen.

my xrandr config first display enabled (lvds1), i.e. before enabling second display (hdmi1):

screen 0: minimum 8 x 8, current 1600 x 900, maximum 32767 x 32767 lvds1 connected primary 1600x900+0+0 (normal left inverted right x axis y axis) 382mm x 214mm panning 1600x900+0+0    1600x900      60.06*+    1440x900      59.89      1368x768      60.00      1360x768      59.80    59.96      1152x864      60.00      1280x720      60.00      1024x768      60.00      1024x576      60.00      960x540       60.00      800x600       60.32    56.25      864x486       60.00      800x450       60.00      640x480       59.94      720x405       60.00      640x360       60.00   dp1 disconnected (normal left inverted right x axis y axis) hdmi1 connected (normal left inverted right x axis y axis)    1920x1080     60.00 +  50.00    59.94      1920x1080i    60.00    50.00    59.94      1680x1050     59.88      1280x1024     75.02    60.02      1440x900      59.90      1280x960      60.00      1152x864      75.00      1280x720      60.00    50.00    59.94      1440x576      50.00      1024x768      75.08    70.07    60.00      1440x480      60.00    59.94      832x624       74.55      800x600       72.19    75.00    60.32    56.25      720x576       50.00      720x480       60.00    59.94      640x480       75.00    72.81    66.67    60.00    59.94      720x400       70.08   vga1 disconnected (normal left inverted right x axis y axis) virtual1 disconnected (normal left inverted right x axis y axis) 

my xrandr config after adding second display ubuntu display manager or xrandr --output hdmi1 --right-of lvds1 --mode 1920x1080:

screen 0: minimum 8 x 8, current 3520 x 1080, maximum 32767 x 32767 lvds1 connected primary 3520x1080+0+0 (normal left inverted right x axis y axis) 382mm x 214mm panning 3520x1080+0+0    1600x900      60.06*+    1440x900      59.89      1368x768      60.00      1360x768      59.80    59.96      1152x864      60.00      1280x720      60.00      1024x768      60.00      1024x576      60.00      960x540       60.00      800x600       60.32    56.25      864x486       60.00      800x450       60.00      640x480       59.94      720x405       60.00      640x360       60.00   dp1 disconnected (normal left inverted right x axis y axis) hdmi1 connected 1920x1080+1600+0 (normal left inverted right x axis y axis) 477mm x 268mm    1920x1080     60.00*+  50.00    59.94      1920x1080i    60.00    50.00    59.94      1680x1050     59.88      1280x1024     75.02    60.02      1440x900      59.90      1280x960      60.00      1152x864      75.00      1280x720      60.00    50.00    59.94      1440x576      50.00      1024x768      75.08    70.07    60.00      1440x480      60.00    59.94      832x624       74.55      800x600       72.19    75.00    60.32    56.25      720x576       50.00      720x480       60.00    59.94      640x480       75.00    72.81    66.67    60.00    59.94      720x400       70.08   vga1 disconnected (normal left inverted right x axis y axis) virtual1 disconnected (normal left inverted right x axis y axis) 

note lvds1 size went 1600x900+0+0 3520x1080+0+0.

does have idea on how find problem ?

thanks

ok think solved problem running fixing panning why first display sliding:

xrandr --output lvds1 --panning 1600x900