I've seen this problem as well. You should be able to replicate it by doing the following:

Open Multiping and add enough hosts that a scrollbar appears for the graphs. Then, rather than grabbing the scroll bar and moving it down, click in the shaded area under the scrollbar. This should cause the scroll bar to move down one "page" width, but every time I do it, it hangs the program. This happens with Multiping 1.01 as well.