Grails : forward instead of redirect and fragment

i use forward instead of redirect (to hide parameters in the url), the problem is that i want to pass a fragment to forward, so my page will scroll to the specified location.
with redirect, this works :

redirect(controller: "mycontroller", action: "myaction", fragment: "anchor")
 

but with forward, it doesn't scroll to the anchor location :

forward(controller: "mycontroller", action: "myaction", fragment: "anchor")
 

any idea how to solve this ??

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