I just started to learn GUI blender python and go through tutorials and API Doc. Long story short I have this script which I put it in blender_scripts_root/startup:

Code:

import bpy class CustomDrawOperator(bpy.types.Operator):    bl_idname = "object.custom_draw"    bl_label = "Simple Modal Operator"    filepath = bpy.props.StringProperty(subtype="FILE_PATH")    def execute(self, context):       print("Test", self)       return {'FINISHED'}    def invoke(self, context, event):       context.window_manager.fileselect_add(self)       return {'RUNNING_MODAL'} class HelloWorldPanel(bpy.types.Panel):    bl_label      = "Hello World Panel"    bl_idname      = "OBJECT_PT_hello"    bl_space_type   = "PROPERTIES"    bl_region_type   = "WINDOW"    bl_context      = "object"    my_test_bool   = bpy.props.BoolProperty(name="my_test_bool", description="a bool property", default=False, options={'ANIMATABLE'}, subtype='NONE', update=None)    def draw(self, context):       layout = self.layout       obj = context.object       row = layout.row()       row.label(text="Hello world!", icon='WORLD_DATA')       row = layout.row()       row.label(text="Active object is: " + obj.name)       row = layout.row()       row.prop(obj, "name")       row = layout.row()       row.prop(self, "bl_context")       row = layout.row()       row.prop(self, "my_test_bool")       row = layout.row()       row.operator("object.custom_draw") def register():    bpy.utils.register_class(CustomDrawOperator)    bpy.utils.register_class(HelloWorldPanel) def unregister():    bpy.utils.unregister_class(CustomDrawOperator)    bpy.utils.unregister_class(HelloWorldPanel) if __name__ == "__main__":    register()

Everything is fine, except this:

Code:

row.prop(self, "my_test_bool")

I can't see it. Can someone tell me what I did wrong?

OBS1 - in the console is this info: "property not found: OBJECT_PT_hello.my_test_bool" <- very strange
OBS2 - I have Blender 2.6.2 running on Windows7.

Thanks in advance for any info about my not working code code.