Polarity and transitive parabolic unitals in translation planes of odd order

A parabolic unital U of a translation plane is called transitive, if the collineation group G fixing U fixes the point at infinity of U and acts transitively on the affine points of U. It has been conjectured that if a transitive parabolic unital U consists of the absolute points of a unitary polarity in a commutative semi-field plane, then the sharply transitive normal subgroupK of G is not commutative. So far, this has been proved for commutative twisted field planes of odd square order, see [1],[5]. Here we prove this conjecture for commutative Dickson planes.