Fuseki UI : add data : error displayed for default graph

[afs]

Version

5.5.0, 5.6.0

What happened?

In the "add data" pane of /#/dataset/ds/upload, the "upload all" button gives an error when "Leave blank for the default graph" for the default graph whether files are listed or not. Individual file upload is not affected.

(I think it really means "load dataset" - while a URI causes ?graph= to appear, no ?default appears and quads formats are accepted)

Relevant output and stacktrace

Are you interested in making a pull request?

None