Once more- leaf icons

[amcoffeegirl]

I have reddish and green leaves. Why are they 2 different colors in different categories?
I don't know what I'm missing here.

 

[qwade]

Tried to figure that out myself .

 

[Brian Van Fleet]

Green = new/unread posts
Brown = no new posts

 

[amcoffeegirl]

Thank you