UserContyrol, MasterPage and AutoEventWireUp

[ABCL]

Hi All
I have UserControl with "AutoEventWireUp="true" Property, and I
have drop this User Control on the Master Page

MasterPage has:
<%@ Master Language="C#" AutoEventWireup="true" ...../>


I have content page using this Master page
If I use "AutoEventWireup="true" on the Content Page's Page
directive, The Page_Load event of UserControl don't fire
and If I use AutoEventWireup="false" on the Content Page's Page
directive, The Page_Load event of the Usercontol does fire,

Actually It should be other way, Can any one answer this question: why
it behavious like this?

Thansk In Advance