create an CauseValidation and an ValidationGroup for TabPanel
in clentide it will call Page_ClientValidate( ValidationGroup ) before changing the tabs and
if Autopostback is true it will perform Page.Validate (ValidationGroup) om server side before ActiveTabCahngef Event
Comments: This ticket was filed for a pre-15.1 version of AJAX Control Toolkit. If this is still an issue in v15.1 or later, please create a new inquiry.
in clentide it will call Page_ClientValidate( ValidationGroup ) before changing the tabs and
if Autopostback is true it will perform Page.Validate (ValidationGroup) om server side before ActiveTabCahngef Event
Comments: This ticket was filed for a pre-15.1 version of AJAX Control Toolkit. If this is still an issue in v15.1 or later, please create a new inquiry.