Fix jump when dragging open

Editor assessment

The subject names the symptom, a jump when dragging the menu open, in the menu scope, which is immediately relatable. The 'fix ... fix' doubling is a minor redundancy. No body, but the 'fixes #20286' footer is well-formed and links the report with the visual evidence, giving the change its context. Type and scope are right and the wording stays short. A small, clear message that does its job; the geometry of the jump lives in the tracker as it should.