diff --git a/src/event_loop/run.rs b/src/event_loop/run.rs
index cb83288..50fb414 100644
--- a/src/event_loop/run.rs
+++ b/src/event_loop/run.rs
@@ -643,6 +643,12 @@ pub( crate ) fn try_run<A: App>( mut app: A ) -> Result<(), RunError>
 		// appeared. Specs are re-queried next frame for drawing.
 		reconcile_overlays( &mut data );
 
+		// Subsurfaces must map with the main surface's first buffer, not a frame later.
+		if !data.first_frame_committed
+		{
+			super::subsurface::reconcile_subsurfaces( &mut data );
+		}
+
 		// Draw any surface that's configured, dirty, and not already waiting
 		// on a frame callback. The compositor decides our cadence — when no
 		// surface qualifies we just loop back to `dispatch(None)` and sleep.
diff --git a/src/event_loop/subsurface.rs b/src/event_loop/subsurface.rs
index 6301782..e6d184f 100644
--- a/src/event_loop/subsurface.rs
+++ b/src/event_loop/subsurface.rs
@@ -285,6 +285,8 @@ pub( crate ) fn reconcile_subsurfaces<A: App>( data: &mut AppData<A> )
 	// parent buffer — the cheap per-frame move.
 	for ( parent, wl ) in dirty_parents
 	{
+		// A bufferless commit is a protocol error on a session-lock surface.
+		if parent == SubsurfaceParent::Main && !data.first_frame_committed { continue; }
 		arm_parent_frame( data, parent, &wl );
 		wl.commit();
 	}