If EL accesses list method e.g. getPageSize() in standard EL notation "vm.list.pageSize" (see below) an NumberFormatException is thrown

{{ <listbox mold="paging" onCreate="self.setPaginal(paging)"
model="@init(vm.list)" >
<!-- not shown -->
</listbox>
<paging id="paging" pageSize="@init(vm.list.pageSize)" />}}

{{java.lang.NumberFormatException: For input string: "pageSize"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:580)
at java.lang.Integer.parseInt(Integer.java:615)
at org.zkoss.zel.ListELResolver.coerce(ListELResolver.java:158)
at org.zkoss.zel.ListELResolver.getValue(ListELResolver.java:71)}}

If EL refers method directly, e.g. vm.list.getPageSize() it works fine.