class ShowPopupOperator(bpy.types.Operator):
       bl_idname = "object.show_popup"
       bl_label = "sample show popup"
       bl_options = {'REGISTER','UNDO'}

       prop1 = bpy.props.IntProperty()
       prop2 = bpy.props.FloatProperty()

       def invoke(self, context, event):
           return context.window_manager.invoke_props_popup(self, event)
       def execute(self, context): # do stuff here
           return {'FINISHED'}

       def draw(self, context):
           col = self.layout.column()
           row = col.row()
           row.label("Hello this the operator drawing")
           row = col.row()
           row.prop(self, 'prop1')
           row = col.row()
           row.prop(self, 'prop2')