poll() as a python '@staticmethod' was too limiting and didnt allow useful base class poll functions in many cases.

now rna functions that dont have a 'self' are automatically assumed '@classmethods'.

de-duplicated poll functions and made some minor tweaks too.

release/scripts/modules/rna_prop_ui.py

@@ -132,6 +132,10 @@ class PropertyPanel():
     bl_label = "Custom Properties"
     bl_default_closed = True
 
+    @classmethod
+    def poll(cls, context):
+        bool(eval("context.%s" % cls._context_path))
+
     def draw(self, context):
         draw(self.layout, context, self._context_path)