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
* @param newType the message type
	 * @since 2.0
	 */
	public void setMessage(String newMessage, int newType) {
		Image newImage = null;
		if (newMessage != null) {
			switch (newType) {
				case IMessageProvider.NONE :
					break;
				case IMessageProvider.INFORMATION :
					newImage = JFaceResources.getImage(DLG_IMG_MESSAGE_INFO);
					break;
				case IMessageProvider.WARNING :
					newImage = JFaceResources.getImage(DLG_IMG_MESSAGE_WARNING);
					break;
				case IMessageProvider.ERROR :
					newImage = JFaceResources.getImage(DLG_IMG_MESSAGE_ERROR);
					break;
			}
		}
		showMessage(newMessage, newImage);
	}
	/**
	 * Sets the minimum page size.
	 *
	 * @param minWidth the minimum page width
	 * @param minHeight the minimum page height
	 * @see #setMinimumPageSize(Point)
	 */
	public void setMinimumPageSize(int minWidth, int minHeight) {