Building a Transparent Overlay That Doesn't Steal Focus with egui on Windows

Thu, 12 Nov 2026 22:55:00 +0900

I built FlexFlyout, an app that shows the playing track when you press the volume keys, with Rust and egui (eframe). Its window has the same needs as the Windows volume indicator: everything outside the panel is see-through, it stays on top, it never takes the focus from the app you’re working in, and it shows up right away. eframe’s options alone weren’t enough for that, so here is what I filled in with direct Win32 calls.

Rust on KANAF Works

Building a Transparent Overlay That Doesn't Steal Focus with egui on Windows