title: Add editable listbox in Glade
body: <p>I use Glade to create GUI, but can't figure out how to insert <code>listbox</code> from the side panel! I can see that a <code>GtkListStore</code> could be created but how to make an editable <code>listbox</code> from that?</p>
  
  <p>I've found that it could be done through adding <code>GtkTreeView</code> structure with the specified <code>GtkListStore</code> pattern. I did some rows this way, but can't put entries in the cells. The cells are inactive and I cannot add text to them!</p>