diff --git a/release/scripts/ui/space_userpref.py b/release/scripts/ui/space_userpref.py
index a97c545e502..202d5cdbed4 100644
--- a/release/scripts/ui/space_userpref.py
+++ b/release/scripts/ui/space_userpref.py
@@ -853,8 +853,8 @@ class USERPREF_PT_addons(bpy.types.Panel):
     bl_region_type = 'WINDOW'
     bl_options = {'HIDE_HEADER'}
 
-    _addons_cats = None
-    _addons_sups = None
+    # _addons_cats = None
+    # _addons_sups = None
     _addons_fake_modules = {}
 
     @classmethod
@@ -875,6 +875,8 @@ class USERPREF_PT_addons(bpy.types.Panel):
         # collect the categories that can be filtered on
         addons = [(mod, addon_utils.module_bl_info(mod)) for mod in addon_utils.modules(USERPREF_PT_addons._addons_fake_modules)]
 
+        # XXX. we need dynamic enums to properly support this.
+        """
         cats = {info["category"] for mod, info in addons}
         cats.discard("")
 
@@ -882,6 +884,8 @@ class USERPREF_PT_addons(bpy.types.Panel):
             bpy.types.WindowManager.addon_filter = EnumProperty(items=[(cat, cat, "") for cat in ["All", "Enabled", "Disabled"] + sorted(cats)], name="Category", description="Filter add-ons by category")
             bpy.types.WindowManager.addon_search = StringProperty(name="Search", description="Search within the selected filter")
             USERPREF_PT_addons._addons_cats = cats
+            
+            [('All', 'All', ''), ('Enabled', 'Enabled', ''), ('Disabled', 'Disabled', ''), ('3D View', '3D View', ''), ('Add Curve', 'Add Curve', ''), ('Add Mesh', 'Add Mesh', ''), ('Animation', 'Animation', ''), ('Development', 'Development', ''), ('Game Engine', 'Game Engine', ''), ('Import-Export', 'Import-Export', ''), ('Mesh', 'Mesh', ''), ('Object', 'Object', ''), ('Render', 'Render', ''), ('Rigging', 'Rigging', ''), ('System', 'System', '')]
 
         sups_default = {'OFFICIAL', 'COMMUNITY'}
         sups = sups_default | {info["support"] for mod, info in addons}
@@ -890,6 +894,7 @@ class USERPREF_PT_addons(bpy.types.Panel):
         if USERPREF_PT_addons._addons_sups != sups:
             bpy.types.WindowManager.addon_support = EnumProperty(items=[(sup, sup.title(), "") for  sup in reversed(sorted(sups))], name="Support", description="Display support level", default=sups_default, options={'ENUM_FLAG'})
             USERPREF_PT_addons._addons_sups = sups
+        """
 
         split = layout.split(percentage=0.2)
         col = split.column()
@@ -1193,6 +1198,37 @@ class WM_OT_addon_expand(bpy.types.Operator):
 def register():
     bpy.utils.register_module(__name__)
 
+    WindowManager = bpy.types.WindowManager
+
+    WindowManager.addon_search = StringProperty(name="Search", description="Search within the selected filter")
+    WindowManager.addon_filter = EnumProperty(
+            items=[('All', "All", ""),
+                   ('Enabled', "Enabled", ""),
+                   ('Disabled', "Disabled", ""),
+                   ('3D View', "3D View", ""),
+                   ('Add Curve', "Add Curve", ""),
+                   ('Add Mesh', "Add Mesh", ""),
+                   ('Animation', "Animation", ""),
+                   ('Development', "Development", ""),
+                   ('Game Engine', "Game Engine", ""),
+                   ('Import-Export', "Import-Export", ""),
+                   ('Mesh', "Mesh", ""),
+                   ('Object', "Object", ""),
+                   ('Render', "Render", ""),
+                   ('Rigging', "Rigging", ""),
+                   ('System', "System", "") 
+                   ], 
+            name="Category",
+            description="Filter add-ons by category",
+            )
+
+    WindowManager.addon_support = EnumProperty(
+            items=[('OFFICIAL', "Official", ""),
+                   ('COMMUNITY', 'Community', ""),
+                  ],
+            name="Support",
+            description="Display support level", default={'OFFICIAL', 'COMMUNITY'}, options={'ENUM_FLAG'})
+
 
 def unregister():
     bpy.utils.unregister_module(__name__)
diff --git a/source/blender/python/intern/bpy_rna.c b/source/blender/python/intern/bpy_rna.c
index a06d44c7e27..5d4a4993f39 100644
--- a/source/blender/python/intern/bpy_rna.c
+++ b/source/blender/python/intern/bpy_rna.c
@@ -2967,9 +2967,15 @@ static PyObject *pyrna_struct_meta_idprop_getattro(PyObject *cls, PyObject *attr
 static int pyrna_struct_meta_idprop_setattro(PyObject *cls, PyObject *attr, PyObject *value)
 {
 	StructRNA *srna= srna_from_self(cls, "StructRNA.__setattr__");
+	const int is_deferred_prop= pyrna_is_deferred_prop(value);
+
+	if(srna && !pyrna_write_check() && (is_deferred_prop || RNA_struct_type_find_property(srna, _PyUnicode_AsString(attr)))) {
+		PyErr_Format(PyExc_AttributeError, "pyrna_struct_meta_idprop_setattro() can't set in readonly state '%.200s.%S'", ((PyTypeObject *)cls)->tp_name, attr);
+		return -1;
+	}
 
 	if(srna == NULL) {
-		if(value && pyrna_is_deferred_prop(value)) {
+		if(value && is_deferred_prop) {
 			PyErr_Format(PyExc_AttributeError, "pyrna_struct_meta_idprop_setattro() unable to get srna from class '%.200s'", ((PyTypeObject *)cls)->tp_name);
 			return -1;
 		}
@@ -2981,7 +2987,7 @@ static int pyrna_struct_meta_idprop_setattro(PyObject *cls, PyObject *attr, PyOb
 
 	if(value) {
 		/* check if the value is a property */
-		if(pyrna_is_deferred_prop(value)) {
+		if(is_deferred_prop) {
 			int ret= deferred_register_prop(srna, attr, value);
 			if(ret == -1) {
 				/* error set */