Question about the global parameter of the Collection

Hi, 

It seems that the global parameter only works after the page get rendered , otherwise the value is always undefined,  is it true ? 

For example,  if you have text box and bind it to a global parameter and bind the <ParamterName>Changed event to a service in the inner mashup,  then you change the text box after the page get loaded , you'll see the global parameter get assigned in the inner mashup . so it works.  

But,  if you put some initial value to the text box and expect the initial value can be passed as global parameter, then whatever event you bind in the inner mashup(including the expression with auto evaluate),  the global parameter in the inner mashup is ALWAYS undefined.  

Regards,

Sean