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
layout.numColumns = 0; 
	layout.makeColumnsEqualWidth = true;
	layout.marginWidth = 0;
	layout.marginHeight = 0;
	layout.horizontalSpacing = convertHorizontalDLUsToPixels(IDialogConstants.HORIZONTAL_SPACING);
	layout.verticalSpacing = convertVerticalDLUsToPixels(IDialogConstants.VERTICAL_SPACING);
	composite.setLayout(layout);
	GridData data = new GridData(
		GridData.HORIZONTAL_ALIGN_END |
		GridData.VERTICAL_ALIGN_CENTER);
	data.horizontalSpan = 2;
	composite.setLayoutData(data);
	composite.setFont(parent.getFont());
	
	
	createButtonsForButtonBar(composite);
	return composite;
}
/* (non-Javadoc)
 * Method declared on Dialog.
 */
protected void createButtonsForButtonBar(Composite parent) {
	buttons = new Button[buttonLabels.length];
	for (int i = 0; i < buttonLabels.length; i++) {
		String label = buttonLabels[i];
		Button button = createButton(parent, i, label, defaultButtonIndex == i);
		buttons[i] = button;
	}
}
/**