File order sources should not be duplicated when editing in the Inventory view

Current Situation

When editing a files order source that does not have a draft version in the Inventory view it happens that the file order source will be duplicated when changing the regular expression twice.

How to reproduce

• create a job chain with a file order source
• deploy the job chain
• open the graphical job chain node view
• open the file order source
• change the regex
• change the regex again

Desired Behavior

File order sources should not be duplicated when changing the regular expression for the file order source.