Empty context menu – useful or an anti-pattern?

In most areas of our browser-based application, the user gets a context menu when he right-clicks an object. In some areas, there are no actions available for the selected object, therefore a right-click doesn't do anything.

Should we show an empty context menu in that case? (i.e. a menu with one inactive "no actions available" entry). Our motivation: it might take our application a while to figure out the possible context menu entries for a certain selection. Therefore we added a spinner image to the context menu which indicates its loading state. The user might be confused if nothing is shown after the loading of the menu has completed.