Removing Nulls from Limited Dashboard Prompts

Summary

Limiting dashboard prompt by other values while removing the null option

Content

Hello,

I've created a dashboard prompt where we're trying to limit the values of the User Person Type by the Assignment Type. The prompt has an apply button at the bottom to allow users to set all the options they want before committing them to the report. I've found when limiting the User Person Type by Assignment Type, a null value appears in the selections. (even if I specify the options myself nor is any data recorded with a null value)

I've read that his is caused by the RPD having the Person Type field defined as "nullable". As an OTBI user, that's not something I have control over. The next attempt was using a SQL Result as the values for the prompt would prevent the null option from appearing. I could use SQL to catch a presentation variable storing the input value of the Assignment Type This might work if the prompt didn't require the "Apply" button but given that we have it I don't think this solution works either.