Any workaround how to choose a text field in Report's filter?

Dima Venglinski

I have a text custom field called Referrer. When somebody fills the form on our website, we automatically create a deal and put a link to the website from which this person landed on our website to the custom field Referrer. It simply needed in order to measure the ROI of different marketing campaigns and understand what websites and campaigns generate the most leads\deals. 

So in the Deals tab, I can create a filter that looks like that, for example - https://take.ms/B7Dmb

But what made me REALLY surprised, is that after upgrading my plan to Pro in order to create custom Reports in the Insights tab, I realized that there is no option to add such a condition as Referrer despite the fact that it exists and perfectly works in Deals tab. Screenshot - https://take.ms/UrotAg

My first thought was that I'm an idiot that can't see an obvious button or tool, but after 2 days with support, it turned out that they Don't Support Text Fields in the Insights tab. 

Maybe you have any advice on how can I create reports in order to measure different website's performance then? Or any tinkering that avoids this stupid limitation? 

Thanks in advance.