void separator_button_actionPerformed(ActionEvent e) {
}
void view_comboBox_actionPerformed(ActionEvent e) {
StructureView view = (StructureView)view_comboBox.getSelectedItem();
viewPanel.setCurrentView(view);
if (((GlobalStructureView)view).getGlobalViewProperties().getHierarchy()
== StructureViewProperties.Hierarchy.DECLARATION) {
granularityCombo.setEnabled(true);
relationsCombo.setEnabled(true);