Fix annotation sorting problem that's been driving me crazy.  Sort descriptors need to be set before loading the document.
Fix annotation sorting problem that's been driving me crazy.  Sort descriptors need to be set before loading the document.

JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim,JackieXie168/skim