How to limit a CTE without using a paramter

How do I make a tracker filter required in a dashboard? I have a CTE query for a full BOM that feeds a dashboard. I have the top level part number as a filter and as long as something is in there, it works fine. I would like that text box to be required in order to refresh so that the user doesn’t get held up with a wide open CTE (although it seems to time out in a reasonable fashion.)

I imagine that I have to put something in the custom validator, but I don’t know where to find what codes are required to make this work.

Any reason why you don’t want to use a required parameter in the BAQ?

And have you tried selecting “Required” in your Tracker Properties and deploying the dashboard?
e.g.
image

Every time you refresh you have to keep typing in the part number, because the system won’t remember what you typed in. So if you make some changes (it’s an updateable dashboard) and you need it to resort/refilter when you hit refresh you have to type in the part number all over again.

I haven’t been able to find this. Can you show me where this is?

Are you talking about this one? Unfortunately that makes all of the fields required, and I only want one of them to be required.

This one
Yes

I wonder if I can do something like this in the dashboard in order to get the parameters directly in the tracker. I’m not sure that this is in quite the same context though.