I received this in a plant trade with this name. Now I am told it is not H. 'Summer Sun'. Sorry the photo isn't more clear.
It is kind of hard to tell from the picture. Yours does seem to be wispier than mine but the flower looks right. If I think about it, I will post mine tomorrow. I may have also put it in the plant data base.
I think the leaves are different than heliopsis. It looks like Rudbeckia lanciniata to me. 'Goldquelle' is a compact double flowered variety. I had 'Golden Glow' for a while which gets about 8 feet tall. It always flopped when it bloomed so I decided to get rid of it.
if it's Rudbeckia lanciniata get it out now. This is the most invasive plant I've ever seen. I let it go for a couple of years, having bought it as something else. Now I can't get rid of it, it spreads from every little piece of root.