Session variable in Basic Repeater web part

Hello,

I am using a Basic Repeater web part and trying to set the "Hide if no record found" property dynamically based on a session variable. It is my understanding that Kentico does not provide any "out of the box" macro to access the session variables, so I've built my own.

I also want to mention that I am using a Filter web part. The Filter web part has 3 drop down lists. By default I am not returning any results (this.WhereCondition = "1=0";). In this case I want to set "Hide if no record found" property to true. As soon as the user selects an option, I build the where condition and return the search results.
At this point I want to set "Hide if no record found" to false.
The goal is to display the error message only if the user selects an invalid combination of search criteria.
I set the session variable in the Filter's "SetFilter()" method based on the user's selection. I almost got it to work but I have a problem: whenever I select the search criteria, I need to click on the "apply filters" twice before I see the "no results found" error message.

Any idea what is causing this problem and how to fix it?

Thank you