Thanks for this! Works perfectly. I think I understand how the second or-join you added is working. I’m happy that I was getting close with my attempt 
. Makes sense to change the variable name.
I saw that @CappieXL had changed their strategy. I wonder with this working, how people see the advantages and disadvantages to the two strategies?
Using query-page with this one means the query could be embedded anywhere and capture all tasks for the namespace, which is nice.