diff --git a/stepmania/src/ActorFrame.cpp b/stepmania/src/ActorFrame.cpp
index d9c0edaf3a..eb79140b45 100644
--- a/stepmania/src/ActorFrame.cpp
+++ b/stepmania/src/ActorFrame.cpp
@@ -134,6 +134,8 @@ void ActorFrame::MoveToHead( Actor* pActor )
 
 void ActorFrame::DrawPrimitives()
 {
+	ASSERT_M( !m_bClearZBuffer, "ClearZBuffer not supported on ActorFrames" );
+
 	if( m_fFOV != -1 )
 	{
 		DISPLAY->CameraPushMatrix();