protected void saveAsPreviousState() {
getUIFacade().setStatusText(GanttLanguage.getInstance().getText("saveCurrent"));
GanttDialogSaveAsPreviousState ps = new GanttDialogSaveAsPreviousState(
this);
ps.show();
if (ps.isSaved()) {
bSaveCurrent.setEnabled(false);
bComparePrev.setEnabled(true);
myPreviousStates.add(ps.getPreviousState());
}