Column filters (select) above header with fixedColumns (min of 2)

LeMont_80

Hello,

I would like to try to integrate column filters (select) above the header with fixedColumns. Can you please guide me on how to do this? I tried to create a test case in jsfiddle however rendering seems to be weird. Anyway, link to jsfiddle is this

https://jsfiddle.net/LeMont_80/uwv4tbcp/

Or if this is already a duplicate questions, please point me to that answered question.

Thanks a lot