Reproduction steps:
1. Create a new project
2. Create a Panel Renderer GameObject (GameObject > UI Toolkit > Panel Renderer)
3. Click “New” button in the Hierarchy to create and assign UI Document
4. Open the UXML Template in UI Staging Mode
5. Create any Standard Element (e.g. GameObject > UI Toolkit > Standard Elements > Button)
6. Undo the change (Ctrl/Cmd + Z)
7. Exit UI Staging Mode and enter it again
8. Observe the UXML Template name in the header
Actual result: UXML Template is marked as dirty
Expected result: UXML Template is not marked as dirty
Reproducible with: 6000.6.0b4, 6000.6.1f1
Not reproducible with: 6000.6.0b3, 6000.7.0a6
Reproduced on: Ubuntu 24.04, macOS Tahoe 26.6 (M4)
Note: Issue is not reproducible in UI Builder