@Override
 protected boolean updateTargetUnderMouse() {
   if (!isTargetLocked()) {
     Collection exclude = getExclusionSet();
     EditPart editPart =
         getCurrentViewer()
             .findObjectAtExcluding(getLocation(), exclude, getTargetingConditional());
     if (editPart != null) {
       editPart = editPart.getTargetEditPart(getTargetRequest());
     }
     boolean changed = getTargetEditPart() != editPart;
     setTargetEditPart(editPart);
     return changed;
   }
   return false;
 }