Starters (I don't know the exact English name, in the German version it's calles "Starter") can't be moved to every position in the panel. I edited a starter's option and removed two other starters from the panel and tried to reorder the starters. It wasn't possible.

When I right-clicked onto the starter and clicked onto "Move" (in the German version "Verschieben"). Then the mouse cursor changed to the "move" cursor, but every starter in the panel was grayed out and it was not possible to move the starter between two other starters.

It was only possible to move it between other panel plugins.