I like this idea, but as a designer I foresee challenges in optimizing what is visible as you add new "functions" when needed. for example, editing a doc, then editing an image to add to the doc. Traditionally each function would live in an app with gui optimized to that function (Word vs Photoshop). Getting these functions to coexist when both are needed would get difficult to display, as image editing has a screen full of tools usually. Not saying it cant be done! I recall Microsoft had a similar idea with OLE (object linking and embedding), where the menus and tools would change depending on what the user clicks on within what is currently displayed. (See https://en.m.wikipedia.org/wiki/Object_Linking_and_Embedding )