This may look as a common seedling. Not special and multi petal/ semi double flower.
It’s a seedling from Flevo Star. Probably from pollen with Blushing Princess.
After discarding several seedlings from Flevo Star with dull single flower this seedling indicates that Flevo Star has (hopefully) doubleness in its genes.
The foliage is nice and large which is the best feature of Flevo Star as well.