I’m still struggling a bit with the association of the ui file with the logic. After checking the plugin made for the AIAA server in NVIDIA, it seems a big chunk of that effect was created by the Wizard, right?
Most segment editor effects create the user interface by Python scripting, but if you need more than just a few widgets then it is worth using a .ui file. I think the only two examples for this are these:
You can either create new segment editor effect using the Extension wizard and update it to use a .ui file (based on the two above modules as examples), or clone one of the two modules above and rename and modify the files to fit your needs.