VS automatic code completion problem

Question

Hi
I have a web application project and there is two .aspx file.  When I writing code in "admin.aspx.cs", automatic code completion is active. I mean When u write "Tex", there will be options all textboxes in the page. But when I writing code in "default.aspx.cs", this automatic completion is not active. I mean there is nothing for suggestion. But this was active before and I dont know how disabled or doesnt work.

How may I enable this automatic suggestion on VS?

Regards.