In the Modeler - Edit > Find advanced (Ctrl+Shift+F) and choose 'Documents' and 'All documents'. – tip from Arjan van IJzendoorn (2014-12-18)
Update: You can filter the search results by the document type, and it does count them for you. As far as I know you cannot filter by module. See this: Note that the image is displaying 140 java actions from a total of 4482 documents (at the top left). The menu to choose docuemnt types to display is top right