Problem when using Tile on maximized MDI windows

I have a strange problem with all MDI applications I create with Delphi 4 or
5. When I use the Tile method to tile all child windows when they are
maximized, they are resized to a size slightly larger than the MDI Client
area. With other words: the child window(s) don't fit in the client area.
Just after the Tile command, the child window(s) are on top of the
client-border of the MDI client window, but when moving a childwindow, the
border re-appears and scrollbars appear (because the child windows don't fit
in the client area).

I get this behavior with all MDI programs (including the standard examples)
which I compile under both Delphi 4 and Delphi 5.

Is anyone familiar with this problem, and (more important) how can I fix it
?

TIA
   Dirk T. Manders