1. In System Settings, navigate to Brightness.
2. Turn on "Adjust automatically" if it is not on already.
3. Go into a much lighter or darker environment, for example by turning lights on/off.
What you see: The slider pops suddenly from one point to another.
What you should see: The slider slides smoothly, accelerating as it leaves its previous value, and decelerating as it reaches its new value.
The brightness slider is just the first ever example of this: it should be a general property of sliders whenever their value is changed non-interactively.
Ubuntu 15.04 r51
1. In System Settings, navigate to Brightness.
2. Turn on "Adjust automatically" if it is not on already.
3. Go into a much lighter or darker environment, for example by turning lights on/off.
What you see: The slider pops suddenly from one point to another.
What you should see: The slider slides smoothly, accelerating as it leaves its previous value, and decelerating as it reaches its new value.
The brightness slider is just the first ever example of this: it should be a general property of sliders whenever their value is changed non-interactively.