the menu bar height does not seem to correspond to that from SystemInformation

i have a form with a menubar below it. i can measure the mouseposition on the from and find that the menu bar is 54 units. however from SystemInformation.MenuHeight i get 19 or 20 units. they don't seem to be very close.

i measure the bottom of the menubar by a mouseover event on the form as i move the mouse from the bottom up it stops measuring at 54 units.

a bit of a puzzle.

follys