Binding a repeat region to an array

Hello,
I’m following this tutorial in order to create an input field containing an array: https://docs.wappler.io/t/working-with-arrays/7701 .
I’m finding that at this step: Select Items under the Array component. This will repeat the button as many times as the items in the array are: , my repeat region doesn’t save the arr items under expression.

Annotation 2020-04-26 185150523×537 29.9 KB