Created attachment 152048 [details] old oxygen dark theme has light and even shadows on all corners of a window SUMMARY The old Oxygen dark theme makes more sense because it has a light-colored and even shadowing on all corners unlike the Breeze dark theme that has stronger or thicker shadow at the bottom of the window. Breeze light maybe doesn't need this but breeze dark doesn't look great.
That's now a shadow, it's a glow, and the Oxygen glow isn't coming to Breeze, sorry; that was a thing for Oxygen's design, not Breeze's. If you prefer it, you're welcome to use the Oxygen Window decoration theme, or customize the color and intensity of the shadows in the Breeze window decoration theme to be more like a glow.