Property Editor: Property value: the 'list' type only allows a 'set' of values. No duplicates allowed!

[Bod]

Once you’ve done the above, delete everything above this line.

Steps to reproduce

1. Create a new note.
2. Add a property to the note - e.g. name: mylist, value= 12345.
3. Change the property type to ‘List’.
4. Add another value - e.g. 67890
5. Try to add a second value equal to the 1st (e.g. 12345). It does not work!

Did you follow the troubleshooting guide? [Y/N]

Yes. Tried in sandbox.

Expected result

Should have a property name ‘mylist’ with an ordered set of values [ “12345”, “67890”, “12345” ]

Actual result

When using the property editor, the duplicate value was not accepted.
Nb. When switching to ‘source mode’, it is possible to enter duplicate values which are then shown in the property editor in ‘visible mode’

Environment

SYSTEM INFO:
Obsidian version: v1.9.10
Installer version: v1.8.4
Operating system: #161-Ubuntu SMP Tue Jul 22 14:25:40 UTC 2025 5.15.0-151-generic
Login status: not logged in
Language: en
Insider build toggle: off
Live preview: on
Base theme: adapt to system
Community theme: none
Snippets enabled: 0
Restricted mode: on

RECOMMENDATIONS:
none

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Additional information

A related bug?: I also note that numbers (integers), in a property that has a list of values, must be in quotes (and if a list of unquoted numbers is used, it confuses the Property Editor value-type checker. The documentation does not specify that numbers (integers) must be quoted. Basically, it appears that all values - numbers, tags, links, etc, - must be quoted.

[WhiteNoise]

@Bod

When using the property editor, the duplicate value was not accepted.

This is not a bug, it’s the intended behavior. Lists can’t have duplicate elements.
You can manually add things in source mode, but it’ll be squashed when we process the properties at some point.

We’ll probably should mark it as invalid in the UI.