title: Gtk.Grid(): how to dynamically modify the number of rows
body: <p>How can I change the simple_table_code from below, to have the possibility of modifying the number of rows of a <code>Gtk.Grid</code> (for example by clicking one of the buttons)? </p>
  
  <p>I suppose I must remove grid section from <code>_init__</code>, but I would like to leave the there buttons. </p>
  
  <p>When I try to do it, the grid doesn't show at all. Also, Is there any more effective way to obtain cell borders beside the method I used?</p>
  
  <pre><code>import gi
  gi.require_version('Gtk', '3.0')
  from gi.repository import Gtk
  from gi.repository import Gdk
  class MyTable(Gtk.Window):
      def __init__(self):
          Gtk.Window.__init__(self, title="Table")
          grid = Gtk.Grid(column_spacing=1,row_spacing=1)
          grid.override_background_color(Gtk.StateFlags.NORMAL,Gdk.RGBA(0.0,0.0,0.0,0.5))
          self.add(grid)
          for i in range (5):
              butt=Gtk.Button(label=i)
              butt.connect("clicked",self.on_button_clicked)
              grid.attach(butt,i,1,1,1)
          for i in range (5):
              for y in range(10):
                  a=Gtk.Label(label=i)
                  a.override_background_color(Gtk.StateFlags.NORMAL,Gdk.RGBA(0.95,0.95,0.95,1.0))
                  grid.attach(a,i,y+1,1,1)        
  
  win = MyTable()
  win.connect("delete-event", Gtk.main_quit)
  win.show_all()
  Gtk.main()
  </code></pre>