There are some post to discuss depends on multi-value for system.xml, (https://magento.stackexchange.com/questions/9935/system-xml-field-dependency)
Below example come from Magento Core Code(app/code/core/Mage/Payment/etc/system.xml
<depends>
<order_status separator=",">processing,processed_ogone</order_status>
</depends>
I have tested this feature for system.xml, it works, but it is not work for widget.xml can anyone tell me how to do "depends on multi-value" for widget.xml?