Bug 65276 [Preferences] Preference dialog should disable OK when okPressed
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
if (isHelpAvailable) {
			createButton(parent, IDialogConstants.HELP_ID,
					IDialogConstants.HELP_LABEL, false);
		}
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.window.Window#createContents(org.eclipse.swt.widgets.Composite)
	 */
	protected Control createContents(final Composite parent) {
		final Control[] control = new Control[1];
		BusyIndicator.showWhile(getShell().getDisplay(), new Runnable() {
			public void run() {
				control[0] = PreferenceDialog.super.createContents(parent);
				
				selectSavedItem();
			}
		});
		return control[0];
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.dialogs.Dialog#createDialogArea(org.eclipse.swt.widgets.Composite)
	 */
	protected Control createDialogArea(Composite parent) {
		final Composite composite = (Composite) super.createDialogArea(parent);
		((GridLayout) composite.getLayout()).numColumns = 3;
		final Control treeControl = createTreeAreaContents(composite);