Hi pickledham,

The dialog filter function is based on silverlight/flash plug-in. You can set the upload type to Silverlight or Flash, if the browser has the plug-in installed, the dialog filter will shows for them.

$uploader->UploadType="Silverlight";

The dialog filter just a client side function, the uploader control will verify the file at server side too. So the user will not allow to upload the file extension which has not set in property "AllowedFileExtensions".

Regards,

Ken