diff -r 894079bece86 -r 5fb8d735fde0 src/widgets/Annotation.js
--- a/src/widgets/Annotation.js	Fri Jan 24 10:53:17 2014 +0100
+++ b/src/widgets/Annotation.js	Thu Feb 06 12:29:31 2014 +0100
@@ -126,6 +126,7 @@
         }
         if (_this.show_annotation_type) {
             _this.$.find(".Ldt-Annotation-Type").text(_annotation.getAnnotationType().title);
+            _this.$.find(".Ldt-Annotation-Type").attr("title", _annotation.getAnnotationType().description);
         }
         _this.$.find(".Ldt-Annotation-Begin").text(_annotation.begin.toString());
         _this.$.find(".Ldt-Annotation-End").text(_annotation.end.toString());