scrolling problem

[Christoph Wollek]

Halo,

if I move fast the scrollbar upwards in the fld show up a lot of lines - 
horrible to look at. They disapear, when I click in the fld.
That effect does not appear, when moving the scroll down. Also not, if I 
click into the scrollbar to get the scroll up.

Any hints, what btns I could click at (I suppose, I have clicked all 
available).

(MC 2.5; Mac OX X - 10,2.2)

Thanks in advance.

Christoph