Attempt to make modifier key changes take affect when the dialogue closes. This means you don't have to restart Fenrir to apply them.

internal/input/router.go

@@ -134,6 +134,9 @@ func (r *Router) Forwarded(device int) []uint16 {
 	return keys
 }
 
+// Idle reports whether all devices have released their routed keys.
+func (r *Router) Idle() bool { return r.empty() }
+
 // Held reports physical state for one device, including consumed keys whose
 // release has not arrived yet.
 func (r *Router) Held(device int) bool { return len(r.keys[device]) != 0 }