diff --git a/release/scripts/ui/buttons_data_armature.py b/release/scripts/ui/buttons_data_armature.py
index db635be763c..75264f5d7ec 100644
--- a/release/scripts/ui/buttons_data_armature.py
+++ b/release/scripts/ui/buttons_data_armature.py
@@ -10,6 +10,7 @@ class DataButtonsPanel(bpy.types.Panel):
 		return context.armature
 
 class DATA_PT_context_arm(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_bone.py b/release/scripts/ui/buttons_data_bone.py
index a3ac86fa841..706c418d0ce 100644
--- a/release/scripts/ui/buttons_data_bone.py
+++ b/release/scripts/ui/buttons_data_bone.py
@@ -10,6 +10,7 @@ class BoneButtonsPanel(bpy.types.Panel):
 		return (context.bone or context.edit_bone)
 
 class BONE_PT_context_bone(BoneButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_camera.py b/release/scripts/ui/buttons_data_camera.py
index c76d2633a51..1321e42b97d 100644
--- a/release/scripts/ui/buttons_data_camera.py
+++ b/release/scripts/ui/buttons_data_camera.py
@@ -10,6 +10,7 @@ class DataButtonsPanel(bpy.types.Panel):
 		return context.camera
 		
 class DATA_PT_context_camera(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_curve.py b/release/scripts/ui/buttons_data_curve.py
index e86af9bf3ab..90d84dc09ed 100644
--- a/release/scripts/ui/buttons_data_curve.py
+++ b/release/scripts/ui/buttons_data_curve.py
@@ -25,6 +25,7 @@ class DataButtonsPanelActive(DataButtonsPanel):
 		return (curve and curve.active_spline)
 
 class DATA_PT_context_curve(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_lamp.py b/release/scripts/ui/buttons_data_lamp.py
index 74c4ba012df..0d384701029 100644
--- a/release/scripts/ui/buttons_data_lamp.py
+++ b/release/scripts/ui/buttons_data_lamp.py
@@ -16,6 +16,7 @@ class DATA_PT_preview(DataButtonsPanel):
 		self.layout.template_preview(context.lamp)
 	
 class DATA_PT_context_lamp(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_lattice.py b/release/scripts/ui/buttons_data_lattice.py
index 3272e1ccf55..505ea6e42e9 100644
--- a/release/scripts/ui/buttons_data_lattice.py
+++ b/release/scripts/ui/buttons_data_lattice.py
@@ -10,6 +10,7 @@ class DataButtonsPanel(bpy.types.Panel):
 		return context.lattice
 	
 class DATA_PT_context_lattice(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_mesh.py b/release/scripts/ui/buttons_data_mesh.py
index f0120b58c6d..2ed52206d7e 100644
--- a/release/scripts/ui/buttons_data_mesh.py
+++ b/release/scripts/ui/buttons_data_mesh.py
@@ -10,6 +10,7 @@ class DataButtonsPanel(bpy.types.Panel):
 		return context.mesh
 
 class DATA_PT_context_mesh(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_metaball.py b/release/scripts/ui/buttons_data_metaball.py
index bf937f212d9..ebb5efb40ca 100644
--- a/release/scripts/ui/buttons_data_metaball.py
+++ b/release/scripts/ui/buttons_data_metaball.py
@@ -9,6 +9,7 @@ class DataButtonsPanel(bpy.types.Panel):
 		return context.meta_ball
 
 class DATA_PT_context_metaball(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_data_text.py b/release/scripts/ui/buttons_data_text.py
index 9b8e1e4d984..49847863d7c 100644
--- a/release/scripts/ui/buttons_data_text.py
+++ b/release/scripts/ui/buttons_data_text.py
@@ -10,6 +10,7 @@ class DataButtonsPanel(bpy.types.Panel):
 		return (context.object and context.object.type == 'TEXT' and context.curve)
 
 class DATA_PT_context_text(DataButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 
 	def draw(self, context):
@@ -171,7 +172,7 @@ class DATA_PT_textboxes(DataButtonsPanel):
 			col.itemR(box, "x", text="X")
 			col.itemR(box, "y", text="Y")
 
-bpy.types.register(DATA_PT_context_text)	
+bpy.types.register(DATA_PT_context_text)
 bpy.types.register(DATA_PT_shape_text)	
 bpy.types.register(DATA_PT_geometry_text)
 bpy.types.register(DATA_PT_font)
diff --git a/release/scripts/ui/buttons_game.py b/release/scripts/ui/buttons_game.py
index 2a1e6adee5b..77581884515 100644
--- a/release/scripts/ui/buttons_game.py
+++ b/release/scripts/ui/buttons_game.py
@@ -330,6 +330,7 @@ class WorldButtonsPanel(bpy.types.Panel):
 		return (rd.engine == 'BLENDER_GAME')
 
 class WORLD_PT_game_context_world(WorldButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 
 	def poll(self, context):
diff --git a/release/scripts/ui/buttons_material.py b/release/scripts/ui/buttons_material.py
index c83f4a65209..af95eec9a68 100644
--- a/release/scripts/ui/buttons_material.py
+++ b/release/scripts/ui/buttons_material.py
@@ -32,6 +32,7 @@ class MATERIAL_PT_preview(MaterialButtonsPanel):
 		self.layout.template_preview(context.material)
 		
 class MATERIAL_PT_context_material(MaterialButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	COMPAT_ENGINES = set(['BLENDER_RENDER', 'BLENDER_GAME'])
 
diff --git a/release/scripts/ui/buttons_object.py b/release/scripts/ui/buttons_object.py
index 37ecf83d846..213fbf17dd6 100644
--- a/release/scripts/ui/buttons_object.py
+++ b/release/scripts/ui/buttons_object.py
@@ -7,6 +7,7 @@ class ObjectButtonsPanel(bpy.types.Panel):
 	bl_context = "object"
 
 class OBJECT_PT_context_object(ObjectButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 
 	def draw(self, context):
diff --git a/release/scripts/ui/buttons_particle.py b/release/scripts/ui/buttons_particle.py
index 8ab31df7543..ad9a82c6824 100644
--- a/release/scripts/ui/buttons_particle.py
+++ b/release/scripts/ui/buttons_particle.py
@@ -24,6 +24,7 @@ class ParticleButtonsPanel(bpy.types.Panel):
 		return particle_panel_poll(context)
 
 class PARTICLE_PT_particles(ParticleButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 
 	def poll(self, context):
diff --git a/release/scripts/ui/buttons_texture.py b/release/scripts/ui/buttons_texture.py
index cb5bca9e26a..3426a879cca 100644
--- a/release/scripts/ui/buttons_texture.py
+++ b/release/scripts/ui/buttons_texture.py
@@ -1,4 +1,3 @@
-
 import bpy
 
 def active_node_mat(mat):
@@ -51,6 +50,7 @@ class TEXTURE_PT_preview(TextureButtonsPanel):
 			layout.template_preview(tex, slot=slot)
 			
 class TEXTURE_PT_context_texture(TextureButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 
 	def poll(self, context):
diff --git a/release/scripts/ui/buttons_world.py b/release/scripts/ui/buttons_world.py
index b0bb27518d4..cfe2410595c 100644
--- a/release/scripts/ui/buttons_world.py
+++ b/release/scripts/ui/buttons_world.py
@@ -19,6 +19,7 @@ class WORLD_PT_preview(WorldButtonsPanel):
 		self.layout.template_preview(context.world)
 	
 class WORLD_PT_context_world(WorldButtonsPanel):
+	bl_label = ""
 	bl_show_header = False
 	COMPAT_ENGINES = set(['BLENDER_RENDER'])
 
diff --git a/release/scripts/ui/space_info.py b/release/scripts/ui/space_info.py
index 58ba96e0181..bf7d30c461d 100644
--- a/release/scripts/ui/space_info.py
+++ b/release/scripts/ui/space_info.py
@@ -96,12 +96,14 @@ dynamic_menu.setup(INFO_MT_file_more)
 '''
 
 class INFO_MT_file_import(dynamic_menu.DynMenu):
+	bl_idname = "INFO_MT_file_import"
 	bl_label = "Import"
 
 	def draw(self, context):
 		self.layout.itemO("WM_OT_collada_import", text="COLLADA (.dae)...")
 
 class INFO_MT_file_export(dynamic_menu.DynMenu):
+	bl_idname = "INFO_MT_file_export"
 	bl_label = "Export"
 
 	def draw(self, context):
@@ -124,6 +126,7 @@ class INFO_MT_file_external_data(bpy.types.Menu):
 		layout.itemO("file.find_missing_files")
 
 class INFO_MT_mesh_add(dynamic_menu.DynMenu):
+	bl_idname = "INFO_MT_mesh_add"
 	bl_label = "Mesh"
 	def draw(self, context):
 		layout = self.layout
diff --git a/release/scripts/ui/space_userpref.py b/release/scripts/ui/space_userpref.py
index b5fdf2fcea0..ef85a608d17 100644
--- a/release/scripts/ui/space_userpref.py
+++ b/release/scripts/ui/space_userpref.py
@@ -24,7 +24,9 @@ class USERPREF_MT_view(bpy.types.Menu):
 		layout = self.layout
 
 class USERPREF_PT_tabs(bpy.types.Panel):
+	bl_label = ""
 	bl_space_type = 'USER_PREFERENCES'
+	bl_region_type = 'WINDOW'
 	bl_show_header = False
 
 	def draw(self, context):
@@ -37,6 +39,7 @@ class USERPREF_PT_tabs(bpy.types.Panel):
 class USERPREF_PT_interface(bpy.types.Panel):
 	bl_space_type = 'USER_PREFERENCES'
 	bl_label = "Interface"
+	bl_region_type = 'WINDOW'
 	bl_show_header = False
 
 	def poll(self, context):
@@ -121,6 +124,7 @@ class USERPREF_PT_interface(bpy.types.Panel):
 class USERPREF_PT_edit(bpy.types.Panel):
 	bl_space_type = 'USER_PREFERENCES'
 	bl_label = "Edit"
+	bl_region_type = 'WINDOW'
 	bl_show_header = False
 
 	def poll(self, context):
@@ -224,6 +228,7 @@ class USERPREF_PT_edit(bpy.types.Panel):
 class USERPREF_PT_system(bpy.types.Panel):
 	bl_space_type = 'USER_PREFERENCES'
 	bl_label = "System"
+	bl_region_type = 'WINDOW'
 	bl_show_header = False
 
 	def poll(self, context):
@@ -315,6 +320,7 @@ class USERPREF_PT_system(bpy.types.Panel):
 class USERPREF_PT_file(bpy.types.Panel):
 	bl_space_type = 'USER_PREFERENCES'
 	bl_label = "Files"
+	bl_region_type = 'WINDOW'
 	bl_show_header = False
 
 	def poll(self, context):
@@ -381,6 +387,7 @@ class USERPREF_PT_file(bpy.types.Panel):
 class USERPREF_PT_input(bpy.types.Panel):
 	bl_space_type = 'USER_PREFERENCES'
 	bl_label = "Input"
+	bl_region_type = 'WINDOW'
 	bl_show_header = False
 
 	def poll(self, context):
diff --git a/release/scripts/ui/space_view3d.py b/release/scripts/ui/space_view3d.py
index f0d1a0dcc6c..d0f60c98a1c 100644
--- a/release/scripts/ui/space_view3d.py
+++ b/release/scripts/ui/space_view3d.py
@@ -886,6 +886,7 @@ class VIEW3D_MT_edit_mesh_edges(bpy.types.Menu):
 
 class VIEW3D_MT_edit_mesh_faces(dynamic_menu.DynMenu):
 	bl_label = "Faces"
+	bl_idname = "VIEW3D_MT_edit_mesh_faces"
 
 	def draw(self, context):
 		layout = self.layout
diff --git a/source/blender/makesrna/intern/rna_render.c b/source/blender/makesrna/intern/rna_render.c
index a67831715a2..3505253b60f 100644
--- a/source/blender/makesrna/intern/rna_render.c
+++ b/source/blender/makesrna/intern/rna_render.c
@@ -269,11 +269,11 @@ static void rna_def_render_engine(BlenderRNA *brna)
 	/* registration */
 	RNA_define_verify_sdna(0);
 
-	prop= RNA_def_property(srna, "idname", PROP_STRING, PROP_NONE);
+	prop= RNA_def_property(srna, "bl_idname", PROP_STRING, PROP_NONE);
 	RNA_def_property_string_sdna(prop, NULL, "type->idname");
 	RNA_def_property_flag(prop, PROP_REGISTER);
 
-	prop= RNA_def_property(srna, "label", PROP_STRING, PROP_NONE);
+	prop= RNA_def_property(srna, "bl_label", PROP_STRING, PROP_NONE);
 	RNA_def_property_string_sdna(prop, NULL, "type->name");
 	RNA_def_property_flag(prop, PROP_REGISTER);
 
diff --git a/source/blender/makesrna/intern/rna_ui.c b/source/blender/makesrna/intern/rna_ui.c
index 34b50e1b3ea..1bb7fe720a6 100644
--- a/source/blender/makesrna/intern/rna_ui.c
+++ b/source/blender/makesrna/intern/rna_ui.c
@@ -592,7 +592,6 @@ static void rna_def_panel(BlenderRNA *brna)
 
 	/* registration */
 	prop= RNA_def_property(srna, "bl_idname", PROP_STRING, PROP_NONE);
-	RNA_def_property_clear_flag(prop, PROP_REGISTER_OPTIONAL);
 	RNA_def_property_string_sdna(prop, NULL, "type->idname");
 	RNA_def_property_flag(prop, PROP_REGISTER);
 
@@ -612,15 +611,15 @@ static void rna_def_panel(BlenderRNA *brna)
 
 	prop= RNA_def_property(srna, "bl_context", PROP_STRING, PROP_NONE);
 	RNA_def_property_string_sdna(prop, NULL, "type->context");
-	RNA_def_property_flag(prop, PROP_REGISTER);
+	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL); /* should this be optional? - Campbell */
 
 	prop= RNA_def_property(srna, "bl_default_closed", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "type->flag", PNL_DEFAULT_CLOSED);
-	RNA_def_property_flag(prop, PROP_REGISTER);
+	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL);
 
 	prop= RNA_def_property(srna, "bl_show_header", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_negative_sdna(prop, NULL, "type->flag", PNL_NO_HEADER);
-	RNA_def_property_flag(prop, PROP_REGISTER);
+	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL);
 }
 
 static void rna_def_header(BlenderRNA *brna)
@@ -693,7 +692,6 @@ static void rna_def_menu(BlenderRNA *brna)
 
 	/* registration */
 	prop= RNA_def_property(srna, "bl_idname", PROP_STRING, PROP_NONE);
-	RNA_def_property_clear_flag(prop, PROP_REGISTER_OPTIONAL);
 	RNA_def_property_string_sdna(prop, NULL, "type->idname");
 	RNA_def_property_flag(prop, PROP_REGISTER);
 
diff --git a/source/blender/python/intern/bpy_rna.c b/source/blender/python/intern/bpy_rna.c
index f12c7b55b0e..f914c3cacea 100644
--- a/source/blender/python/intern/bpy_rna.c
+++ b/source/blender/python/intern/bpy_rna.c
@@ -3194,7 +3194,7 @@ static int bpy_class_validate(PointerRNA *dummyptr, void *py_data, int *have_fun
 	PyObject *item, *fitem;
 	PyObject *py_arg_count;
 	int i, flag, arg_count, func_arg_count;
-	char *identifier;
+	const char *identifier;
 
 	if (base_class) {
 		if (!PyObject_IsSubclass(py_class, base_class)) {
@@ -3269,6 +3269,8 @@ static int bpy_class_validate(PointerRNA *dummyptr, void *py_data, int *have_fun
 		item = PyObject_GetAttrString(py_class, identifier);
 
 		if (item==NULL) {
+
+			/* Sneaky workaround to use the class name as the bl_idname */
 			if(strcmp(identifier, "bl_idname") == 0) {
 				item= PyObject_GetAttrString(py_class, "__name__");
 
@@ -3280,7 +3282,8 @@ static int bpy_class_validate(PointerRNA *dummyptr, void *py_data, int *have_fun
 				}
 			}
 
-			if (item==NULL && (flag & PROP_REGISTER_OPTIONAL)==0) {
+
+			if (item == NULL && (((flag & PROP_REGISTER_OPTIONAL) != PROP_REGISTER_OPTIONAL))) {
 				PyErr_Format( PyExc_AttributeError, "expected %.200s class to have an \"%.200s\" attribute", class_type, identifier);
 				return -1;
 			}