title: OpenGL + gtkglextmm + glade
body: <p>when I am programming with "gtkmm", there is a widget <strong>"Gtk::DrawingArea"</strong>.<br/>
  I can program that widget <em>"by hand"</em> (so write the code) or more elegant way is to use "glade" user interface designer, where I can do the same <em>"graphically"</em>.</p>
  
  <p>Now I am trying to connect OpenGL with gtkmm through "gtkglextmm" library. In that library, there is a widget <strong>"Gtk::GL::DrawingArea"</strong> - but this widget <strong>"IS NOT"</strong> available in glade.</p>
  
  <p>So is there any way to program with "OpenGL + gtkglextmm" using "glade" (for the "graphical user interface" part)?</p>
  
  <p>Thanks.</p>