In Impress's slide pane on the left: 1. scroll to the bottom (so that the scrollbar "touches" the bottom) 2. make the mouse wheel scroll up one click Result: the scrollbar jumps to the top instead of scrolling up one notch. This does not happen if your scrollbar is not "touching" the bottom.
Created attachment 53411 [details] screencast
NOT reproduced with LOdev 3.5.0beta2 4ca392c-760cc4d-f39cf3d-1b2857e-60db978 Ubuntu 10.04.3 x86 Linux 2.6.32-37-generic Russian UI GNOME 3 specific?
Nope, actually fixed in 3.4.4 it seems!