The generic panel would be much better if bags worked. They do not work with Bridge CS4/5/6 & CC on Windows 7.
Example code...
<?xml version='1.0' encoding='UTF-8'?><xmp_definitions><xmp_schema prefix="my" namespace="http://ns.adobe.com/MyNamespace/"
description="The My Schema" label="$$$/xmp/my/mylabel=My" ><xmp_property name="mybag" category="external" type="bag"
label="$$$/xmp/my/mybag=My Bag" element_type="text" /></xmp_field></xmp_schema></xmp_definitions>
Also Bridge CS6 and Bridge CC share the same folder for the xml files!
They should be different.
CS6
C:\Users\<username>\AppData\Roaming\Adobe\XMP\Custom File Info Panels\4.0\custom
CC should be...
C:\Users\<username>\AppData\Roaming\Adobe\XMP\Custom File Info Panels\5.0\custom