Is it a performance issue, if i put mutableState fields in model class which is use in lazyColumn items?

As supposed to what? Are there any other methods to populate a LazyColumn?

@Dominaezzz I mean something like this class UIModel { someField by mutableStateOf(true) otherField : String } @Composable fun ListItem(uimodel: UIModel) { Box { clickListener { someField = false } } }

Ohhh. No there isn't a performance issue you should be particularly worried about.