So many comments suggesting different UI frameworks with varying levels of cross-platform support.<p>Guys, I hate to say this, just use Java. Its fully cross-platform with a complete UI toolkit that looks native and isn't slow. You're not going to find anything else thats as complete or performant. Java has been focused on this niche forever.<p>I bet you use Java GUI's all the time without even knowing it. Most of you every day. Tons of IDE's, database visualizers, and other dev tools are made with Java GUI's.<p>Every Jetbrains tool, DBeaver, DB Visualizer, MySQL Workbench, other stuff I'm too lazy to look up. If you have a tool thats not web with a big UI, its Electron or Java 90% of the time.