I have found an issue in datebox, this is my zul code:

<datebox id="viewShiftTableDateBox"
sclass="centerTextAlign"
format="dd MMMM yyyy (EEEE)"
width="200px"
locale="it"
mold="rounded"
hflex="1"
/>

when I choose a sunday in datebox, datebox returns on the web page a string of this format "15 aprile 2012 (undefined)" (datebox_IT.png)
I wuould expect "15 aprile 2012 (domenica)".
If I choose a different day, from monday to saturday, datebox return correct format text.

The behavior is even worse if I use locale="en".
On the calendar header of datebox, "22 April 2012 (Sunday)" is reported as Saturday, and so the other days.
There is a shift in datebox header (sun mon tue ..) but there is not a shift in dates...

Datebox component has no issues if i use format="dd MMMM yyyy (EEE)" -> 15 aprile 2012 (Sun) in both locales.

I made tests of zk-fiddle too useing divverent versions of zk, but th eproblem persists.

Please help.
Thanks.