I have added a menu item in edit control block(ECB) in document library(using following msdn article http://msdn.microsoft.com/en-us/library/ms473643.aspx)
Now i found that the custom action(menu Item) in ECB is displayed for both document item and document folder. So how to apply custom action only for document item?
Are you using list as your RegistrationType?
Try using ContentType as your RegistrationTypeand specify the guid of the Document Content Type (I think its 0x0101) in your RegistrationID.