According to the DOM and given that your are using the dialog object of InDesign DOM, you should use addEventListener :
But I never gave this a try myself. The Dialog UI is great but one can find ScriptUI smoother.
The place you referred to (indesignjx.de - except that I was in their version with 12 in the version information, rather than the version with 10 you cited) is where I found out about event listeners, but when I looked further in there to find possible event types/names, I couldn't find any event type or name that seemed to have anything to do with clicking or change. That was the basis for my comment below my little coding example to the effect that I couldn't find an example of (or an approach to) using an event listener. Thanks for trying.
I am not sure you do something wrong. I have the feeling the event handling mechanism isn't really implemented with the Dialog class. Although the doc states it, no official event types can be attached at it seems. Dialog's philosophy is more about "if user clicked ok, then grab all data you need from the dialog and keep on working".
Once again, if you need events mechanisms, consider ScriptUI.
Unless I am wrong,
Not sure if I understand your fragment correctly. It seems as if you mixing two different ways of building a window. 'dialogRows' is a property in InDesign's dialogs object (i.e. you created the window using app.dialogs.add()), and none of the controls in that model has the onChange method. onChange is part of a different window model (ScriptUI), which you used if you defined your window with "new Window ('dialog')".
If you use InDesign's dialog model you need event listeners to monitor activity in the window. If you use ScriptUI, you can use onChange, onChanging, onActivate, onDeactivate, etc. You may need event listeners occasionally, but usually not.
I couldn't say better but it's true it's confusing as DOM states the dialog object can have listeners.
Thanks. That's what I was coming to believe, but I didn't really want to have to go in and rephrase the dialog box construction. You are also correct that in my example I had used InDesign's dialogs object - I just didn't show that code line for simplicity.
I guess I have my work cut out for me - not really any thinking, but lots of rephrasing!
So I'll give you credit for having the correct answer. Thanks!