Fixed handling of halfedges in selection nodes (Not updated on geometr change).

Closes #112

libs_required/ACG/Scenegraph/StatusNodesT.cc

@@ -132,6 +132,13 @@ StatusNodeT<Mesh, Mod>::
 update_cache()
 {
   if (invalidGeometry_) {
+
+    // Vertices, Edges and Faces use the mesh geometry.
+    // However Halfedge selection buffers are computed.
+    // Therefore we have to invalidate them when
+    // the geometry changes to force a recomputation.
+    halfedgeCacheInvalid_ = true;
+
     bbMin_ = Vec3d(FLT_MAX, FLT_MAX, FLT_MAX);
     bbMax_ = Vec3d(-FLT_MAX, -FLT_MAX, -FLT_MAX);
 
@@ -143,6 +150,7 @@ update_cache()
     }
 
     invalidGeometry_ = false;
+
   }
 
   /*