Application Scoping - Inconsistent Behaviour on New Dictionary Entries

[The SN Nerd]

For the 'Catalog Item' table, I am trying to create a new Dictionary Entry in a Scoped Application.
I get the following error message:

"Invalid 'Table' selected on the Dictionary Entry record. The 'Catalog Item' table is in application 'Global', but the current application is 'DevKIT/RDB'. The 'Table' field can only select 'Global' tables with read access enabled."

AS shown below, 'Read access' is enabled for 'Catalog Item':

You might then say 'Allow configuration' isn't checked!

However, take a look at the User table:

Note that 'Can read' is checked, and 'Allow configuration' is not checked.
However, I am able to create fields in my Application Scope for that table.

I then selected 'Can create' and 'Can update' on the Catalog Item table to reflect the same setting as the User table. 

It matches the exact same Application Access setting as the user table, for which I can create Scoped fields, but I still cannot add a Dictionary Entry to the table.
Only setting 'Allow configuration' allows me to do this, but I don't need to do this for the User table.

So, what is going on here? 
Is the error message incorrect, and/or is this a defect?

[Chris Sanford1]

Hey Paul,

I was curious, and I think I might have found the answer! If you configure the form layout of the sys_db_object form you can see that there is actually a column with the label 'Allow New Fields' (alter_access). It is set to true on sys_user but false on sc_cat_item.

Also of interest, if you set allow configuration to true on sys_user and then back to false, you can't add columns outside global scope anymore!

I think it's a glitch that you could do this on sys_user in the first place. Submit a HI ticket and hopefully this gets added to their list of HI problems that they say they'll fix one day!

[The SN Nerd]

I have raised an Incident on HI.

We will see what they say.

I wonder what happens if I brute force these changes to be able to create a field, then apply my Application to an instance that does not have that configuration, what happens?

[Chris Sanford1]

Hopefully a HI Problem, I've been responsible for several of those being created.

As far as brute forcing it, I think you will need allow configuration enabled on sc_cat_item in that instance before you apply your application. You shouldn't be able to add fields to a global table that doesn't allow cross-scope configuration. I think the defect is that you're able to on sys_user, and other tables where alter_access is true, but allow configuration is false out of box. The alter_access field automatically gets set when allow configuration is changed, so ServiceNow just needs to bulk update that field on legacy tables.

[The SN Nerd]

I guess we will find out!

It is interesting, because the error message would indicate that only 'Create' is needed for dictionary entries

"The 'Table' field can only select 'Global' tables with read access enabled"

It may just be that this is misleading.

I wouldn't expect to be able to create Business Rules on sc_cat_item, but based on that error message, I would expect I could create fields.