Isn't comparing one costume to an entire concept kind of apples vs. oranges? Argue that the costume idea was stolen if you want, but as far as I can tell from IMDB, Breaking Glass had nothing to do with computers whatsoever. Sounds like it was a music-themed movie to me.

Hmmm. Well for me it's the critical aspect of O'Connor's song which is the most interesting; not just what she's wearing per-say. Tron succeeds creatively for entirely different reasons.

Bear in mind that the visual style of the characters in Tron was engineered from animation technology that predated the movie by about five years. The whole backlit neon outline look was being experimented with.

The costume in that act likely seems so Tronlike because the song is about technology changing the world, so beyond simply neon glowies, the suit is made to look like actual circuits.

There's definitely a confluence of concepts and execution between that act and Tron. But it was likely just convergent evolution. It's always possible that one of the costume designers for Tron had seen the Breaking Glass act from a couple of years earlier though. A possible giveaway more than the circuit designs is the helmet the lead singer is wearing. The contours and the back of the helmet that covers the neck look exactly like Yori's helmet in Tron.