ASP.NET No postback on asp:ImageButton

Question

Hello,

I have an ASP page with an asp:DropDownList (with AutoPostBack="true") so that when the user changes it, it reload the appropriate data.

Under that control i have a list of UserControls, that includes a tinymce editor (tied to an asp:TextBox) and an asp:ImageButton to save the data.

When clicking on the ImageButton, the applications send the postback data via ajax to the same page (__EVENTARGUMENT, __EVENTTARGET, etc...). Why does it load that ajax page, and how do i prevent it? I'm updating the value in the DB in the OnClick event handler on the ImageButton, so all I need to do, is get ride of that ajax call.

Any ideas?