 private extension AddWebFeedWindowController {
 	
 	private func updateUI() {
-		addButton.isEnabled = urlTextField.stringValue.mayBeURL
+		addButton.isEnabled = urlTextField.stringValue.mayBeURL && selectedContainer() != nil
 	}
 
 	func cancelSheet() {

	}

	func selectedContainer() -> Container? {
		return folderPopupButton.selectedItem?.representedObject as? Container
	}
}

			return
		}
		
		guard let container = selectedContainer() else { return }
		AddWebFeedDefaultContainer.saveDefaultContainer(container)

		delegate?.addFeedWindowController(self, userEnteredURL: url, userEnteredTitle: userEnteredTitle, container: container)
