KCM: Explain what being the Primary screen means
Right now we don't explain what this does, so users are free to guess what it does and create their own expectations, most of which will not be met and cause dissatisfaction and bug reports. So let's clearly explain what it does.
There are no visual changes when onl a single screen is connected.
|KScreen KCM||KScreen KCM with help button hovered or clicked|