Bug 305703 [Viewers][CommonNavigator] remembered contributions can leak when using filters
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
structuredViewerManager
							.initialize(ext.internalGetContentProvider());
				}
			}
			rootContentProviders = extractContentProviders(findRootContentExtensions(aNewInput));
		}
	}
	public IExtensionStateModel findStateModel(String anExtensionId) {
		if (anExtensionId == null) {
			return null;
		}
		INavigatorContentDescriptor desc = CONTENT_DESCRIPTOR_REGISTRY
				.getContentDescriptor(anExtensionId);
		if (desc == null) {
			return null;
		}
		INavigatorContentExtension ext = getExtension(desc);
		if (ext == null) {
			return null;
		}
		return ext.getStateModel();
	}
	/**
	 * <p>
	 * Return all of the content providers that are relevant for the viewer. The
	 * viewer is determined by the ID used to create the
	 * INavigatorContentService ({@link #getViewerId() }). See
	 * {@link #createCommonContentProvider() } for more information about how
	 * content providers are located for the root of the viewer. The root
	 * content providers are calculated once. If a new element is supplied, a