Steps to Reproduce

 Selection of comboitem not working for combobox inside a popup that sit in front of a highlighted window dialog (same issue with both 9.6.5 and 10.0.0):

https://zkfiddle.org/sample/n2peoh/7-Can-t-select-comboitem-in-popup-combobox

Current Result

Can't select comboitem in popup
 

Expected Result

can select a comboitem in a popup
 

Debug Information

Workaround

• make the popup with a combobox as a child of the highlighted window