What does the grey checkmark in the layer do?

[Aasmund]

Hello, first post here.


I just bought Paintstorm Studio yesterday and find it the best tool for anime, I even dare to say it beats Clip Paint Studio.
I see this grey checkmark in the layer. What does that do?

[support]

It's a mark of a reference layer, used for magic wand and fill tool. Also, you can bind a hotkey to show/hide reference layer.