Securities Register Add-On; Adding Security Stmt, Key does not exist in collection error

This error may occur when adding a Security Statement to an existing Account.

When clicking the Security page on an existing Account, and there is no linked Security Statement, the user can add a linked Security Statement by clicking the 'Open' button on the Security Item grid.

If the logged in User has the following permission set to deny 'SecurityStmt.BranchUpdate' and the User has no Branch default set up in User Preferences; Clients; General page then when the Security Statement is saved the following error would occur:

'Key does not exist in collection'