Here's a Kotlin observation on primitive types. I was using scrollTo(data.size) but getting an ambiguous resolution error because my data field was initially Int. scrollTo, in JavaFX, provides two overloaded functions: Int and generic T. The earlier example in Hamza's thread, I punted and used String. To convert data to Int, you need to unbox the argument to the scrollTo call. This version changes the data field, add() calls, and the scrollTo arguments.