public AbstractEnvelopeReportPieCanvas(Composite parent, final DateRangeCombo combo, int style) {
super(parent, combo, style);
transactionService.addEntityListener(this);
topEnvelopeSource = getInitialEnvelopeSource();
envelopeStack.push(topEnvelopeSource);
addKeyListener(
new KeyAdapter() {
public void keyPressed(KeyEvent e) {
if (e.keyCode == SWT.ESC) {
if (envelopeStack.size() > 1) {
popSourceEnvelope();
regenerateChart();
}
}
}
});
}
