I want to create a ribbon button that will work with all kinds of lists. I mean, the same custom action should work against lists, document libraries, Announcement lists, etc..
Also. It should work regardless of the content types contained in the list.
What should be the custom action definition for this?
I found that setting the RegistrationType to ContentType and RegistrationID to 0x solves this problem. 0x corresponds to Content type “Item”, so this will work for all types of lists, even the ones for which content type management is not enabled.