OpenDoc was an IBM/Apple technology for a document-centric OS. Modules could be dragged into a single document: a Photoshop part for a picture; a dictionary object too. Taligent (who no longer exist) were set up to pursue the object orientated dream, in the 'Pink' project categorising the world into People, Places and Things [ref]. Their work is cited by StarDock (the Object Desktop for Windows) who are only now using similar technology.
The dream of OpenDoc never came to fruition, losing out to Microsoft's better marketed OLE, but it's fascinating to read those excited articles in 1994, when so many people thought of the whole world through an OO window. It's easy to do, when object orientation is so new. It's a shame everything is so much more complicated than that.