Problems Switching Swatch. Swatch is stuck on Fill and will not switch to stroke.

Hello,

I am trying to do a lesson and where I had to put one image on top of another. I tried Oppacity when I want it to be transparent, but it only made the color lighter. 

My issue now is since the last update, my swatch is having trouble switching from fill to stroke. When I want stroke, it still goes back to fill. Even if I switch it around, or I press Alt-X, it still does that. How do I fix this?

I tried to switch it on the left side of the panel, and it goes back to fill when I want a swatch.