cannot select two-way data binding property on a dropdown list con

I have a dropdownlist control in a formview and I am trying to enable 2 way
databinding. Only, the option is not available. I look at the "Edit
Databinding" option of another DDL control in the same formview and it is
available The only difference is that the DDL (where the two-way data binding
property in not available) is inside a panel control.

Would a DDL inside a panel control cause the two-way data binding property
to be unavailable???

FYI... This DDL is bound to a table via a datasource control and I need two
way binding for the insert and edit template of the formview.

Thanks