Dismiss the fully-charged state when clicking on the indicator

[snwh]

trafficstars

When the battery is fully charged and still on AC power, the indicator shows a green icon. Allow this to be user-dismissed by clicking on the indicator to "confirm" and change the icon to white.

[danirabbit]

I think this makes sense since we allow dismissing other types of notifications by focusing the widget such as with Terminal tabs and obviously the notifications indicator itself

[snwh]

If we can't change the colour of the icon we can simply use battery-full-symbolic since it is the same icon without the green.