void headerShowToolTip (int x) {
	String tooltip = headerGetToolTip (x);
	if (tooltip == null || tooltip.length () == 0) return;

	if (toolTipShell == null) {
		toolTipShell = new Shell (getShell (), SWT.ON_TOP | SWT.TOOL);
		toolTipLabel = new Label (toolTipShell, SWT.CENTER);
		Display display = toolTipShell.getDisplay ();
		toolTipLabel.setForeground (display.getSystemColor (SWT.COLOR_INFO_FOREGROUND));
		toolTipLabel.setBackground (display.getSystemColor (SWT.COLOR_INFO_BACKGROUND));
		for (int i = 0; i < toolTipEvents.length; i++) {
			header.addListener (toolTipEvents [i], toolTipListener);
		}
	}
	if (headerUpdateToolTip (x)) {
		toolTipShell.setVisible (true);
	} else {
		headerHideToolTip ();
	}
}