'Load extra models" appears only for 'experimental'

viewer.html

@@ -76,7 +76,7 @@
         <div id='help_button' title='Help'>?</div>
         <div id='download_button' title='Download 3d model (.obj & .x3d formats)'></div>
         <div id='menu_button' title='Menu'></div>
-        <div id='extra_models_button' title='Load extra models'></div>
+        <div id='extra_models_button' title='Load extra models' class='experimental'></div>
         <div id='align_button' title='Run least squares fitting algorithm (Gauss-Newton) for camera heading and location using markers.
 Instructions:
   1. Use approximate location control on the map to change initial approximation for the algorithm.