I understood which is the reason of the issue I have. Using facelets, the page I was describing (the one using the listshuttle component) is a component which is inserted in another page, the main page. In the main page I load the prototype library (prototype.js) and I noticed that also the listshuttle loads the prototype library by itself. Even if the 2 prototype libraries have the same version (1.6), the one used by the richfaces component has some added lines of code and the 2 libraries are somehow in conflict at generate the error at runtime (only on IE).
My question is: what should I do? Do I have to load only the prototype library of the listshuttle component or there is a way to make coexist the 2 libraries (Notice that I need the prototype library also in other pages)?
I had a similar issue which unfortunately had a different resolution:
I too have miserable results on IE6 (less on IE7) and am quite surprised that more people haven't as well. Have you absolutely verified with Firebug debugger that your are loading two prototypes
into rendered page?