Disabling active window hint kills panel and dock surfaces (cosmic_corner_radius_layer_v1 protocol error)

[ReyMoss]

Summary

On COSMIC 1.5.0, disabling the active window hint makes cosmic-panel and the dock disappear immediately. The cosmic-panel process stays alive but its surfaces are destroyed, and the session log floods with cosmic_corner_radius_layer_v1 protocol errors. The hint cannot be disabled at all: the only way to get the panel back is to restore the setting and restart cosmic-panel. Reproduced on two machines (Intel iGPU laptop and a Surface Pro 6).

Environment

• COSMIC 1.5.0 (cosmic-comp 1.5.0, cosmic-panel 1.5.0, cosmic-session 1.5.0)
• NixOS unstable 26.11, snapshot 2026-08-16, session started from GDM

Steps to reproduce

1. Log into a COSMIC session with panel and dock visible.
2. Set ~/.config/cosmic/com.system76.CosmicComp/v1/active_hint to false, either through Settings or by writing the file directly.
3. Panel and dock vanish at once. pgrep cosmic-panel still shows the process running.

Logs

journalctl --user, hundreds of identical lines within the same second

Aug 18 14:28:33 reylab cosmic-session[2540]: Protocol error 1 on object cosmic_corner_radius_layer_v1@80
Aug 18 14:28:33 reylab cosmic-session[2540]: Protocol error 1 on object cosmic_corner_radius_layer_v1@80
Aug 18 14:28:33 reylab cosmic-session[2540]: Protocol error 1 on object cosmic_corner_radius_layer_v1@80
(repeats identically, ~hundreds of lines in one second)

Notes

Possibly related: pop-os/cosmic-comp#2654 (corner_radius LayerHookId check for layer surfaces, shipped in 1.5.0) and #2913 (corner radius and layer-shell errors with a different trigger). This report is on stock 1.5.0 where that fix is already included.