Keep plasmoid Active when PM is disabled, so you don't need to dig in the systray popup to turn it on again.
Usually you turn PM off temporarily when watching a movie or so. When your battery is fully charged, the icon
goes away. So you wonder where your icon went and have to dig in the systray popup to find it.
So it's a nice convenience to have the icon stay active while PM is turned off so you can easily turn it back on again.
And the tooltip now also tells you.