I have an IBM Thinkpad R51, with a touchpad that has a slightly strange (but default for my model) behaviour where-by the very right hand side of the touchpad acts as a scroll bar. Touching the touchpad on this side and moving it up/down scrolls the buffer up and down. Nothing unordinary about this. It's sensitive to speed and touch, so if I press hard and drag fast, it's bound to go faster than if I barely touch and barely drag... in fact, there's a threshold where it'll continue scrolling down/up if a certain amount of pressure is put on it. One thing I love about touchpads
The bug is movement related, so I haven't been able to pin it down until recently. Scrolling up, then moving my finger slightly to the left and scrolling down and back towards the corner again. It's very easy to reproduce, and I'm currently uploading a video that displays both the position of my finger on the touchpad and the scrollbar portion of mIRC. It seems to only apply when the cursor is over the nicklist. As a result of this bug, the frame that the mIRC buffer and scrollbar is in completely disappears (a la minimise all). I'll post the link once it's finished uploading.