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
*/
	private void setShellSize(int width, int height) {
		getShell().setSize(width, height);
		constrainShellSize();
	}
	/**
	 * Show the new message
	 */
	private void showMessage(String newMessage, Image newImage) {
		
		if (message.equals(newMessage) && messageImage == newImage)
			return;
		message = newMessage;
		if (message == null)
			message = ""; 
		messageImage = newImage;
		if (!showingError) {
			
			messageLabel.setText(message);
			messageLabel.setImage(messageImage);
			messageLabel.setToolTipText(message);
		}
	}
	/**
	 * Shows the preference page corresponding to the given preference node.
	 * Does nothing if that page is already current.
	 *
	 * @param node the preference node, or <code>null</code> if none
	 * @return <code>true</code> if the page flip was successful, and
	 * <code>false</code> is unsuccessful