i don't know if there is an event for a double mouseclick, i dont think so. But i think there are other ways to get the same effect as a double click on something. But you can't implement any code in the builder, you only can define a function on the right side of your builder, in the part where it says 'Code : '.
But I've never used it anyway. Why don't you just implement your eventhandler by yourself in a java file?
Thank you for your reply.
I have implemented it by myself, not using javafx builder, just like your advice.
For my other event handlers are all using javafx, so I think it will be look elegant, or say it neat using this in my all event handlers. :)