Bug 24157 [Dialogs] MessageDialog needs to setFocus on default button
As the MessageDialog by default has no other widgets to set focus on we need to set focus on the default button to prevent it getting slammed by the default SWT behaviour.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/MessageDialog.java
*/
	public final static int NONE = 0;
	/**
	 * 	Constant for a dialog with an error image (value 1).
	 */
	public final static int ERROR = 1;
	/**
	 * 	Constant for a dialog with an info image (value 2).
	 */
	public final static int INFORMATION = 2;
	/**
	 * 	Constant for a dialog with a question image (value 3).
	 */
	public final static int QUESTION = 3;
	/**
	 * 	Constant for a dialog with a warning image (value 4).
	 */
	public final static int WARNING = 4;
	/**
	 * Labels for buttons in the button bar (localized strings).
	 */
	private String[] buttonLabels;
	/**
	 * The buttons. Parallels <code>buttonLabels</code>.
	 */
	private Button[] buttons;
	/**
	 * Index into <code>buttonLabels</code> of the default button.
	 */
	private int defaultButtonIndex;