To describe my question, let me explain how I work. View elements such as buttons, checkboxes and numberfields have among their properties that you can define an action. I write that action handling code in a method in the Custom panel. In the view element properties box, in the field 'Action' I only write the call to that method. That way, when I want to edit the code for that action I don't have to dig down into the view element tree, all the code is directly accessible in the Custom panel.

I now have two simulations that use the 'evolution event' capability of EJS. Can I do the same thing with the code in the 'Events for ODE evolution' box?

The reason I ask is that in the upper section, with the code for the zero condition, the code returns a value.

Of course, for one thing the method in the Custom panel must then not be declared as a 'void' method; void methods are methods that do not return a value. Java being a type-aware language I assume that when the returned value is type double you declare 'double' instead of 'void'.

Yeah, I could just try that and see if it works, but I decided to ask anyway.