diff --git a/panda/src/dxgsg9/dxGeomMunger9.I b/panda/src/dxgsg9/dxGeomMunger9.I
index eee877c668..223e6478cb 100644
--- a/panda/src/dxgsg9/dxGeomMunger9.I
+++ b/panda/src/dxgsg9/dxGeomMunger9.I
@@ -31,6 +31,6 @@ DXGeomMunger9(GraphicsStateGuardian *gsg, const RenderState *state) :
   }
   // Set a callback to unregister ourselves when either the Texture or the
   // TexGen object gets deleted.
-  _texture.set_callback(this);
-  _tex_gen.set_callback(this);
+  _texture.add_callback(this);
+  _tex_gen.add_callback(this);
 }
diff --git a/panda/src/dxgsg9/dxGeomMunger9.cxx b/panda/src/dxgsg9/dxGeomMunger9.cxx
index 44729ae0cd..e9b9ba498e 100644
--- a/panda/src/dxgsg9/dxGeomMunger9.cxx
+++ b/panda/src/dxgsg9/dxGeomMunger9.cxx
@@ -28,6 +28,9 @@ DXGeomMunger9::
     unref_delete(_filtered_texture);
     _reffed_filtered_texture = false;
   }
+
+  _texture.remove_callback(this);
+  _tex_gen.remove_callback(this);
 }
 
 /**