'Clear all the panes.'

def _clearAll(self, action):

    self.elements = []
    self.comp.set_left_pane('', '')
    self.comp.set_right_pane('', '')
    self.showingPage = None
    self.leftElement = None
    self.sensitive_all(False)
    self.delbut.set_sensitive(False)
    self.clusterbut.set_sensitive(False)
