It’s not there - 
- undocumented afaik. Never seen it covered anywhere. And since ordering widgets containers is such a nuisance, this should come in handy.
- pull the items array from the list
- set it to some temp array (manipulating the list directly will not work)
- insert what is needed at index into the temp array
- set list items
- wrap it a nifty function
- do tell if it works as intended
Should work the same with tile view. fingers crossed