public static void main (String [] args) {
	display = new Display ();
	shell = new Shell (display);
	shell.setLayout(new GridLayout());
	coolBar = new CoolBar(shell, SWT.FLAT | SWT.BORDER);
	coolBar.setLayoutData(new GridData(GridData.FILL_BOTH));
	ToolBar toolBar = new ToolBar(coolBar, SWT.FLAT | SWT.WRAP);
	int minWidth = 0;
	for (int j = 0; j < 5; j++) {
		int width = 0;
		ToolItem item = new ToolItem(toolBar, SWT.PUSH);
		item.setText("B" + j);
		width = item.getWidth();
		/* find the width of the widest tool */
		if (width > minWidth) minWidth = width;
	}
	CoolItem coolItem = new CoolItem(coolBar, SWT.DROP_DOWN);
	coolItem.setControl(toolBar);
	Point size = toolBar.computeSize(SWT.DEFAULT, SWT.DEFAULT);
	Point coolSize = coolItem.computeSize (size.x, size.y);
	coolItem.setMinimumSize(minWidth, coolSize.y);
	coolItem.setPreferredSize(coolSize);
	coolItem.setSize(coolSize);
	coolItem.addSelectionListener(new SelectionAdapter() {
		@Override
		public void widgetSelected(SelectionEvent event) {
			if (event.detail == SWT.ARROW) {
				CoolItem item = (CoolItem) event.widget;
				Rectangle itemBounds = item.getBounds ();
				Point pt = coolBar.toDisplay(new Point(itemBounds.x, itemBounds.y));
				itemBounds.x = pt.x;
				itemBounds.y = pt.y;
				ToolBar bar = (ToolBar) item.getControl ();
				ToolItem[] tools = bar.getItems ();
				
				int i = 0;
				while (i < tools.length) {
					Rectangle toolBounds = tools[i].getBounds ();
					pt = bar.toDisplay(new Point(toolBounds.x, toolBounds.y));
					toolBounds.x = pt.x;
					toolBounds.y = pt.y;
					
					/* Figure out the visible portion of the tool by looking at the
					 * intersection of the tool bounds with the cool item bounds. */
			  		Rectangle intersection = itemBounds.intersection (toolBounds);
			  		
					/* If the tool is not completely within the cool item bounds, then it
					 * is partially hidden, and all remaining tools are completely hidden. */
			  		if (!intersection.equals (toolBounds)) break;
			  		i++;
				}
				
				/* Create a menu with items for each of the completely hidden buttons. */
				if (chevronMenu != null) chevronMenu.dispose();
				chevronMenu = new Menu (coolBar);
				for (int j = i; j < tools.length; j++) {
					MenuItem menuItem = new MenuItem (chevronMenu, SWT.PUSH);
					menuItem.setText (tools[j].getText());
				}
				
				/* Drop down the menu below the chevron, with the left edges aligned. */
				pt = coolBar.toDisplay(new Point(event.x, event.y));
				chevronMenu.setLocation (pt.x, pt.y);
				chevronMenu.setVisible (true);
			}
		}
	});

	shell.pack();
	shell.open ();
	while (!shell.isDisposed ()) {
		if (!display.readAndDispatch ()) display.sleep ();
	}
	display.dispose ();
}