null reference exception

http://www.expandframework.com/forum/8-discussion/3923-object-reference-error-when-trying-to-view-the-detail-view-of-dash-board-definition/6283.html
Update error handling

http://www.expandframework.com/forum/6-bugs/3924-ambiguousmatchfound-exception-in-13-2-8-6/6285.html
apply appearence rule font only to model rules

http://www.expandframework.com/forum/6-bugs/3856-invalidoperationexception-cannot-cast-appearanceattribute-to-ixpandappearanceruleproperties.html?start=6#6286
13.2.8.7