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
if (errorMsgAreaBackground == null) {
					errorMsgAreaBackground =
						JFaceColors.getErrorBackground(
							messageLabel.getDisplay());
					errorMsgImage =
						JFaceResources.getImage(PREF_DLG_IMG_TITLE_ERROR);
				}
					
				normalMsgAreaBackground = messageLabel.getBackground();
				messageLabel.setBackground(errorMsgAreaBackground);
				messageLabel.setImage(errorMsgImage);
				titleImage.setImage(null);
			}
		}
		titleArea.layout(true);
	}
	/**
	 * Sets whether a Help button is available for this dialog.
	 * <p>
	 * Clients must call this framework method before the dialog's control
	 * has been created.
	 * <p>
	 *
	 * @param b <code>true</code> to include a Help button, 
	 *  and <code>false</code> to not include one (the default)
	 */
	public void setHelpAvailable(boolean b) {
		isHelpAvailable = b;
	}