I have the same. If I scroll the references' preview it will not update unless I select a new reference from another file (for example the resulted references are from x.cpp and x.hpp and I scrolled when it was a selected ref from cpp, but then selecting a ref from hpp, then the preview starts working again).
The same thing is happening to me with Preview toolbar too.
WinXP, SE13.0.1 latest hotfix (r17), Preview and References toolbars floating on a 2nd screen.
Daniel