Dynamic index id

[George]

See also:

Duplicate ids - warnings in the console

You need to give both static id and dynamic id (with dmx-bind:ID) to get it to work. The static id - you can use into your expressions, the dynamic id is for the browser. So in your case it will be something like: id="checkbox_idRecord" dmx-bind:id="'checkbox_idRecord' + $index" the expression you have will continue to work with the static id.