Onchange to update another select collection?

I have two select box control in the lightbox. What I want to do is when a select box’s value is selected or value has changed, I want to update collection of another select box because these both select box is dependent to each other.

However when I trigger onchange event of the select box and attempts to update the collection of another select box at the same time, the entire lightbox suddenly disappear but the entire screen still modal overlay. How to solve this problem?

linking lightbox selects has to be done manually, i.e. you’ll have to redefine ‘options’ elements of the dependent select box on parent change.
Please check this example (you can find it in your scheduler package as well):
docs.dhtmlx.com/scheduler/sample … htbox.html