OK, I'll fix that.

@RaymondLim @peterflynn  But, what should the behavior be if focus is in left-half of the viewer (that does not have scroll bars) or over scroller when there are no scroll bars (i.e. color property) ? The scroll wheel behavior is to scroll page.

Should keyboard navigation be the same as scroll wheel? FYI, PageUp and PageDown seems to make sense to scroll page when there is no inner scroller, but scrolling for up-arrow and down-arrow just seems weird to me.

Or maybe scroll wheel behavior should be changed?