TreeModel and visible rows

[Seika van Olstroem <seika vanolstroem gmail com>]

Hello list,

how can i determine the number of visible rows of currently displayed 
TreeModel?

The reason why i'm asking is that i'm trying to only append as much rows 
as the tree model can display without the need to be scrolled by an 
ScrolledWindow.

Thanks in advance.

best regards,
Seika van Olstroem