run the attached example
click the button (observe the logs in the browser console)
"onBind" is called 2 times every time the nested added dynamically
"onUnbind" is only called once
"onBind" called only once
(or if technically necessary to call onBind 2x, call onUnbind also 2x)
Unmatched onBind/onUnbind pairs make it difficult to initialize/cleanup client side libraries properly.
The performance overhead of rendering the inner borderlayout 2x should be avoided.
Surrounding the inner <borderlayout> with a <div> fixes the problem, and onBind gets only called once as expected