Bug 41927 [Dialogs] Selecting in PreferenceDialog generates too many invalid entries
20030825 If you select an entry, close the dialog and then reopen it selecting anotehr entry will result in a "this page has invalid values" although you selected nothing.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
update();
		return true;
	}
	/**
	 * Shows the "Page Flipping abort" dialog.
	 */
	private void showPageFlippingAbortDialog() {
		MessageDialog.openError(getShell(), JFaceResources.getString("AbortPageFlippingDialog.title"), 
		JFaceResources.getString("AbortPageFlippingDialog.message")); 
	}
	/**
	 * Updates this dialog's controls to reflect the current page.
	 */
	protected void update() {
		
		updateTitle();
		
		updateMessage();
		
		updateButtons();
		
		setSelectedNode();
	}
	/* (non-Javadoc)
	 * Method declared on IPreferenceContainer
	 */
	public void updateButtons() {
		okButton.setEnabled(isCurrentPageValid());
	}