Extender control ... cannot extend controls of type ...

Hi all,

I have a custom ImageButton that inherits from the standard ImageButton.

When I try to extend this button with ConfirmButtonExtender, I receive the following error:

Extender control 'cbeDelete' cannot extend 'ibDelete'.
Extender controls of type 'AjaxControlToolkit.ConfirmButtonExtender' cannot extend controls of type 'MyControls.ImageButton'.

Thx in advance

Any suggestions?

Even I am having same problem.