Add a 'dismiss' button to the Welcome Banner

[icaria36]

@Rhod

Its posible add a “dismiss” button or “close” button (x).

@Heddson

Is it possible to add a dismiss-button, or is that perhaps out of scope for this component?

If the answer is that there are settings to remove the banner based on trust level (and also for staff) then fine. Still, it would be useful to know, if possible, please.