diff --git a/internal/graphicsdriver/metal/graphics_darwin.go b/internal/graphicsdriver/metal/graphics_darwin.go
index ef9ac1be9..38a10b21a 100644
--- a/internal/graphicsdriver/metal/graphics_darwin.go
+++ b/internal/graphicsdriver/metal/graphics_darwin.go
@@ -97,6 +97,8 @@ func NewGraphics() (graphicsdriver.Graphics, error) {
 	g := &Graphics{}
 
 	if runtime.GOOS != "ios" {
+		// Initializing a Metal device and a layer must be done in the main thread on macOS.
+		// Note that this assumes NewGraphics is called on the main thread on desktops.
 		if err := g.view.initialize(systemDefaultDevice); err != nil {
 			return nil, err
 		}