question on criteria for deleting a category

[Jack]

I'm updating the handbook chapter on Categories, and have run into  
something I can't explain.  If I display the Categories View and right  
click on a category, sometimes "Delete" is enabled, and sometimes it is  
not.  For categories with existing transactions, if Delete is enabled,  
I am prompted for another category for reassigning the transactions.   
So, mere presence of transactions does not disable the Delete action.

I've tried actually looking into the xml file, and that has only  
confused me further.  There seem to be several odd things going on, and  
I'm not sure if they are related or not.  In these examples, both  
categories of interest also have matching payees.

- In many cases, the transaction itself has a MEMO which is not visible  
anywhere in the GUI, which only shows the MEMOs of the appropriate  
SPLIT, depending on which ledger (account, category, payee) I look at.
- I don't see any consistency or pattern in whether there is a PAYEE in  
the split for the CATEGORY, although I think it is almost always  
present in the split for the account.  There also seems to be no way to  
change this, as you can't edit a transaction in the context of a  
category.

Is there something I'm not understanding, or might this just be another  
case where I have strange data?

Jack