In the "What's new" page in Stardog Studio of version v3.6.0, there is the following item:
Named graph dropdown menu when importing, exporting, and dropping from a database (VET-1811)
As I experience it, this removes the option to load data into a named graph using the "Load Data" button on the "Databases" tab, unless the named graph already exists?
It is still possible to create a named graph when importing data through Studio.
The dropdown menu presents all existing named graphs and the search input for existing named graphs also supports creating a new named graph when a valid, new IRI is searched for.
For instance, if you enter a valid IRI for a named graph that does not exist in your database you will be given an option for Use <[INPUT]>. By selecting this option and importing data a new named graph will be created.