Documentset doesn't inherit the Library/Site settings to open documents in the client application.
Documentset doesn't inherit the Library/Site settings to open documents in the client application. When I change the setting to open files in client application and create a new document in a document set it keeps using Office Online. When I create a new document directly from the library it does open the client Office application.
Probably this is by design. But it shouldn't. Please let us know if this is fixed in the modern UI of document sets.
Alfons Riesebeek commented
I Agree, we need the the local version to work in large documents
If Office Online had all the features of the rich client this would not be a problem. But now it is!