It can happen that checking Primary visibility of a Local surrounding .hdr in Stellar mode seems not to work when also Infite size is active under Transformation tab.
If Infinite size is active the surrounding lies behind the background color of the Stellar viewer. Therefor you cannot see it even when Primary visibility is turned on.
- Go to Edit > Preferences…
- In the Preferences window select User interface > Appearance
- Change the Viewer background color to black:
The surrounding should now be visible even if Infinity size is checked.