Fuse version 1.0.0 (build 13426), MacOS Sierra 10.12.5
When running “fuse preview” from a terminal an item just named NSMenuItem is where the “Close Viewport” item is supposed to be.
I often see this when Fuse is starting, but it quickly transforms into “Close Viewport”, however if local preview does not work (e.g. compile-errors in Uno/Foreign Code), it’s stuck.!
Here’s a screenshot.