ListView: Fast scroll down, scrollbar slider jumps to the end

I currently develop an application with custom ListView CellItems. Now I have a very strange behaviour with scrolling in this ListView. If I scroll fast down the scroll slider directly jumps to the end and I can't continue scrolling. But the items displayed in the ListView are not the last items in the ListView.

I attached a video and a runnable project that shows up this problem:

Video: https://www.dropbox.com/s/8dib3e1d3jmv7vp/scroll_bug_fast_scroll.avi?dl=0
Example Project: https://www.dropbox.com/s/70q1r6th7i7hu9r/fast_scroll_down_scrollBug.zip?dl=0
Windows7 Mouse Settings: https://www.dropbox.com/s/cvgchxwa7vz7e4j/scroll_bug_mouse_settings.png?dl=0

Another problem that sometimes occurs (not in this video) is that, if I scroll up very fast, the hole UI freezes for seconds. After that freezing the scrolling continues.