Newb question about coloring

Is there any way to fill a vector shape with a color other than it’s own?
At the moment if I make a grey circle, click white, and use the fill tool, the circle is colored in grey. I would like to be able to make a grey circle, click white, and color it in white.

Is this even possible? Ah, I feel so stupid. I see all of these things made with pencil and even tutorials but all of them either skip over coloring or do it in some ridiculously hard way.

First, are you sure it’s not that annoying feature where you have to first click the fill tool and then click the color you want? Or, sometimes it even makes me select the color an extra time because it’s just buggy.

If one of those things doesn’t work, then I don’t know what to tell you. Personally, I generally stick to the bitmap layers because drawing vectors properly so they can be filled in is a pain.