select in group header

I want to show up a select dropdown in group header of datatable. i managed to do it. but it does not stay focused when i click on it… it closes as soon as i click on it. Here’s what i am doing
var groupHeader = { id:“ColumnKey”,header:[{content:“columnGroup”, closed:false, batch:group, groupText:“FN 30FH 30 Dollar Rolls”, colspan:columns.length, css: css},
],template: “#ColumnKey#”, sort:“int”}

it doesn’t even let me click other option. It shuts that fast

groupText:" < select class=dollarrolls> < option value=1>FN 30< option value=2>FH 30</ select> Dollar Rolls"

webix team, please help