SysML accept event action validation

[RobCDeJong]

I want to model an event with SysML but the accept event action keeps giving me the validation warning "action is missing the required child element: Trigger".
Even when I add a new child Trigger, via the properties dialog, the validation warning does not go away.

The same type of validation warning (missing child element: Signal) occured when I am trying to model the send signal action.  

Can someone explain to me what I am doing wrong or is it a bug in the validation?

cheers,
Rob