[cforms] union case="integer-widget"

[Karel Vervaeke]

When you run the example below, you get a ClassCastException,
when you make the change indicated by the comments, the example works fine
Should it be considered a bug or not?
-- def --
<fd:field id="case-widget">
 <fd:datatype base="integer"/> <!-- change this to string and it works -->
</fd:field>
<fd:union id="extra-widgets" case="case-widget">
 <fd:widgets>
   <fd:field id="extra-field">
     <fd:datatype base="string"/>
   </fd:field>
 </fd:widgets>
</fd:union>
-- bind --
<fb:value id="case-widget" path="pathToAnInteger" />
-- template --
<ft:union id="extra-widgets">
 <ft:case id="0">
   <ft:widget id="extra-field"/>
 </ft:case>
</ft:union>
(partial) workaround:
If you only need on-load binding, you can work around the problem by 
making case-widget/datatype/@base="string" and putting this in the binding:

<fb:value id="case-widget" path="concat('',pathToAnInteger)" 
direction="load"/>