UI Builder window does not mark the document as dirty when the "Unset" action is performed on an element of a nested document

How to reproduce:
1. Open the “DirtyUIBuilder.zip“ project
2. Open the “Document 2.uxml” file in UI Builder
3. Select the “Example” element in the UI Builder Hierarchy
4. Right-click on the “Focusable” attribute and click “Unset”
5. Observe the UI Builder

Expected result: The tab header is marked as dirty (with a “*” at the end of the name)
Actual result: The tab header is not marked as dirty (no “*” at the end of its name)

Reproducible in: 2021.3.45f1, 2022.3.50f1, 6000.0.23f1

Reproduced on: Windows 11 Pro (23H2), macOS 14.6.1 (M1)(by the reporter)
Not reproduced on: No other environment tested

Note: If the “Unset“ action is done on an element of the same UI Document, the UI Builder gets marked as dirty