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 (store != null
					&& store.needsSaving()
					&& store instanceof IPersistentPreferenceStore) {
					try {
						((IPersistentPreferenceStore) store).save();
					} catch (IOException e) {
						MessageDialog.openError(getShell(), JFaceResources.getString("PreferenceDialog.saveErrorTitle"), 
						JFaceResources.format("PreferenceDialog.saveErrorMessage", new Object[] { page.getTitle(), e.getMessage()})); 
					}
				}
			}
		}
	}
	/**
	 * Notifies that the window's close button was pressed, 
	 * the close menu was selected, or the ESCAPE key pressed.
	 * <p>
	 * The default implementation of this framework method
	 * sets the window's return code to <code>CANCEL</code>
	 * and closes the window using <code>close</code>.
	 * Subclasses may extend or reimplement.
	 * </p>
	 */
	protected void handleShellCloseEvent() {
		
		cancelPressed();
	}
	/**
	 * Notifies of the pressing of the Help button.
	 * <p>