Bug 336684 [JFace] NPE in Tray Dialog
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/TrayDialog.java
* Creates a new help control that provides access to context help.
	 * <p>
	 * The <code>TrayDialog</code> implementation of this method creates
	 * the control, registers it for selection events including selection,
	 * Note that the parent's layout is assumed to be a <code>GridLayout</code>
	 * and the number of columns in this layout is incremented. Subclasses may
	 * override.
	 * </p>
	 * 
	 * @param parent the parent composite
	 * @return the help control
	 */
    protected Control createHelpControl(Composite parent) {
		Image helpImage = JFaceResources.getImage(DLG_IMG_HELP);
		if (helpImage != null) {
			return createHelpImageButton(parent, helpImage);
		}
		return createHelpLink(parent);
    }
    
    /*
     * Creates a button with a help image. This is only used if there
     * is an image available.
     */
	private ToolBar createHelpImageButton(Composite parent, Image image) {
        ToolBar toolBar = new ToolBar(parent, SWT.FLAT | SWT.NO_FOCUS);
        ((GridLayout) parent.getLayout()).numColumns++;
		toolBar.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_CENTER));
		final Cursor cursor = new Cursor(parent.getDisplay(), SWT.CURSOR_HAND);
		toolBar.setCursor(cursor);