
even if there is no scroll bar visible and needed, the InertiaScrollViewer swallows all mouse wheel events which otherwise would "scroll" through a focused ComboBox for example.
Additionally nested ScrollViewers become totally unusable, even just clicking on the scrollbar-buttons does weird things with the outer InertiaScrollViewer -- and I only just replaced a non-problematic outer normal "ScrollViewer" with an "InertiaScrollViewer".