variable of combo box after selection not working in content2\balloon

I have some combo boxes inside a content balloon which opens on click. After selecting the first combo box the next combo box should be populated. This logic seems to work fine outside of content/balloon but not inside. 

alertSelectedRegion is the variable of combobox of text datatype and is passed to list filter condition on combo change event. Inside content/balloon it looks like alertSelectedRegion does not populate selected value from combo box. If I drag all this outside of content/balloon it works fine

Can you isolate a sample and upload that file? That will be much easier to understand your questions and to help you.