A known problem.
We work around it by having the query show the details and the tree to allow quick access to the child.
I think that I've found out what was wrong.
Graham, maybe your issue is different.
Bit embarrassing but I missed out the Launch Action options on the Query and Report Designer General settings section
You are right, even with the General setting present I'm seeing the same behaviour as the bug suggests
I'll use the incident tree for opening