Bug 287621 [CommonNavigator] Add more tracing
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
if (visibleExtensionIds.isEmpty()) {
			return NO_EXTENSION_IDS;
		}
		return (String[]) visibleExtensionIds
				.toArray(new String[visibleExtensionIds.size()]);
	}
	public INavigatorContentDescriptor[] getVisibleExtensions() {
		List visibleDescriptors = new ArrayList();
		NavigatorContentDescriptor[] descriptors = CONTENT_DESCRIPTOR_REGISTRY
				.getAllContentDescriptors();
		for (int i = 0; i < descriptors.length; i++) {
			if (assistant.isVisible(descriptors[i].getId())) {
				visibleDescriptors.add(descriptors[i]);
			}
		}
		if (visibleDescriptors.isEmpty()) {
			return NO_DESCRIPTORS;
		}
		return (INavigatorContentDescriptor[]) visibleDescriptors
				.toArray(new INavigatorContentDescriptor[visibleDescriptors
						.size()]);
	}
	INavigatorContentDescriptor[] getActiveDescriptorsWithSaveables() {
		List result = new ArrayList();
		NavigatorContentDescriptor[] descriptors = CONTENT_DESCRIPTOR_REGISTRY
				.getContentDescriptorsWithSaveables();
		for (int i = 0; i < descriptors.length; i++) {
			if (assistant.isVisible(descriptors[i].getId())
					&& assistant.isActive(descriptors[i])) {
				result.add(descriptors[i]);