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
preferenceManager
				.getElements(PreferenceManager.PRE_ORDER)
				.iterator();
		while (nodes.hasNext()) {
			final IPreferenceNode node = (IPreferenceNode) nodes.next();
			if (node.getPage() != null) {
				Platform.run(new SafeRunnable() {
					public void run() {
						if (!node.getPage().performCancel())
							return;
					}
				});
			}
		}
		setReturnCode(CANCEL);
		close();
	}
	/* (non-Javadoc)
	 * Method declared on Window.
	 */
	public boolean close() {
		List nodes = preferenceManager.getElements(PreferenceManager.PRE_ORDER);
		for (int i = 0; i < nodes.size(); i++) {
			IPreferenceNode node = (IPreferenceNode) nodes.get(i);
			node.disposeResources();
		}
		return super.close();
	}
	/* (non-Javadoc)
	 * Method declared on Window.