Thread:Property talk:Subproperty of/subproperty of and forms and ask

I have a property 'technicals skill' and his subproperty 'technicals java skill' 1/ when I create a form trying to fill a technicals skill, it doesn't propose the allowed values defined for his subproperties, is there any way ? 2/ when I mixe the use of 'subproperty of' and include some allowed values in the parent proporty, and the {{#ask queries returns an error : "Unexpected non-MediaWiki exception encountered, of type "RuntimeException"

thanks for help.