ctions take effect on button release.</li>
  <li>Precsion modifiers Shift and Control can thus be pressed at any
  time for controlling rate of rotation, translation or zooming.</li>
</ol>
</li>

<li>Add support for multiple secondary-selection and partial
  highlightning of secondary-selectable sub-items. This requires new
  signals to be emitted from <tt>TGLViewer</tt>:
<pre>
   virtual void MouseOver  (TObject *obj, UInt_t state); // *SIGNAL*
   virtual void ReMouseOver(TObject *obj, UInt_t state); // *S