Users usually just want to change the brightness of the current output,and seldom wants to change the brightness of all outputs simultaneously.Hence, actions without explicitly specifying output (scrolling on appletand pressing brightness keys) should act on the active output.
Test plan:
- in multimonitor setup, scroll on applet with mouse
- verify that only display with applet changes brightness
- in multimonitor setup, scroll on applet with touchpad
- verify that only display with applet changes brightness
- in multimonitor setup, press brightness keys
- verify that only the active display changes brightness