Webel recommends (usually) display the header of a Package, Model, ModelLibrary, or Profile in the 'tab' (rather than 'top')

MagicDraw/Cameo gives display options 'tab' or 'top' for Header Position. If you are showing an overview diagram with just packages and not contents or element list you may wish to use 'top' mode, but usually Webel recommend 'tab' mode.