Glass was macOS-only because it rode setVibrancy. Windows 11 22H2 has a
first-party equivalent in setBackgroundMaterial, so the mode now resolves
its backing per platform instead of per-OS-check: macOS keeps vibrancy,
Windows 11 gets DWM acrylic / tabbed / mica, and everything older stays on
Clear. No third-party native addon.
Two Windows-specific details the mapping has to respect. DWM only paints
the client area of a transparent window (electron#49443), so glass-capable
Windows chat windows are born transparent with the opaque themed
backgroundColor covering them while glass is off — a live Clear/Glass
toggle then needs no window recreate. And Windows exposes three backdrops
for four frost rungs, so the two heaviest both resolve to mica; the mapping
stays total so a frost saved on a Mac still renders.
Glass support is computed once from os.release() and shared: main uses it
for the persisted default and every window, preload publishes it to the
renderer so the UI can't offer a mode the window can't back.
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