diff --git a/panda/src/glstuff/glGraphicsStateGuardian_src.cxx b/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
index 5a8c16001b..63ee8dcf4d 100644
--- a/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
+++ b/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
@@ -2588,6 +2588,15 @@ issue_shade_model(const ShadeModelAttrib *attrib) {
 void CLP(GraphicsStateGuardian)::
 issue_shader(const ShaderAttrib *attrib) {
   ShaderMode *mode = attrib->get_shader_mode();
+  if (mode == 0) {
+    if (_shader_context != 0) {
+      _shader_context->unbind();
+      _shader_context = 0;
+      _shader_mode = 0;
+    }
+    return;
+  }
+  
   Shader *shader = mode->get_shader();
   CLP(ShaderContext) *context = (CLP(ShaderContext) *)(shader->prepare_now(get_prepared_objects(), this));
 
@@ -2602,9 +2611,11 @@ issue_shader(const ShaderAttrib *attrib) {
       context->bind(mode);
       _shader_context = context;
     }
+    _shader_mode = mode;
   } else {
     // Use the same shader as before, but with new input arguments.
     context->rebind(_shader_mode, mode);
+    _shader_mode = mode;
   }
 }
 
diff --git a/panda/src/pgraph/shaderAttrib.I b/panda/src/pgraph/shaderAttrib.I
index 10d9f5b3a7..04d9f4992a 100755
--- a/panda/src/pgraph/shaderAttrib.I
+++ b/panda/src/pgraph/shaderAttrib.I
@@ -20,11 +20,10 @@
 ////////////////////////////////////////////////////////////////////
 //     Function: ShaderAttrib::Constructor
 //       Access: Private
-//  Description: Use ShaderAttrib::make() to construct a new
-//               ShaderAttrib object.
+//  Description: xyz
 ////////////////////////////////////////////////////////////////////
 INLINE ShaderAttrib::
-ShaderAttrib() {
+ShaderAttrib(void) {
 }
 
 ////////////////////////////////////////////////////////////////////
diff --git a/panda/src/pgraph/shaderAttrib.h b/panda/src/pgraph/shaderAttrib.h
index 7553cfc8b8..cf787c69b1 100755
--- a/panda/src/pgraph/shaderAttrib.h
+++ b/panda/src/pgraph/shaderAttrib.h
@@ -39,7 +39,7 @@
 class EXPCL_PANDA ShaderAttrib: public RenderAttrib {
 
 private:
-  INLINE ShaderAttrib();
+  INLINE ShaderAttrib(void);
 
 PUBLISHED:
   static CPT(RenderAttrib) make(ShaderMode *sm);