add a button choice on alv toolbar in wda

Hello Experts,

I want add a button choice on alv toolbar. I already insert the choice button indeed I see the button correctly.

Now I want insert the list of action with the following code:

<<

>>

With this code my web-interface retuns this message: "500 SAO INTERNAL SERVER ERROR. ERROR ACCESS via null object reference not possible. (termination rabax_state)". The dump is in "cl_wdr_utilities=>construct_mime_url".

Do you have any ideas? Do you have any examples?

Thanks in advance.

Best Regards,

Marino