title: SSRS Multi-Value Blank
body: <p>I have a SSRS report with a few dropdowns that are chained together. Basically a item is selected from dropdown 1 which then populates dropdown 2 and so on. The issue I am having is that in dropdown 3, which is a multi-value populated from a query I want to allow no selection.</p>
  
  <p><strong>Problem #1</strong><br>
  Although that report parameter is set to allow blanks, it will not let me deselect all values. I get a required error.</p>
  
  <p><strong>Problem #2</strong><br>
  In my stored procedure I have the parameter in question being filtered by an <code>IN</code> statement, which will not work if a blank is coming though as I want the blank to skip that filter.</p>
  
  <p><strong>Problem #3</strong><br>
  The dropdown #3 may not have any values once the other 2 are selected.</p>
  
  <p>I feel that I am using the multi-value incorrectly causing all 3 issues. Any help is appreciated.</p>