Steps to reproduce:
1. Create a new project
2. Create UI Document (Create > UI > UI Document)
3. Double-click on the newly created UI Document to open UI Builder window
4. Resize the UXML Document output to the smallest possible size
5. Press “Fit Canvas” button
Actual results: Canvas does not appear in the Viewport
Expected results: Canvas appears in the middle of the Viewport
Reproducible with versions: 2023.3.0b7, 6000.0.51f1, 6000.1.7f1, 6000.2.0b5
Not reproducible with versions: 2021.3.52f1, 2022.3.63f1, 2023.3.0b6
Tested on (OS): macOS Sequoia 15.4 (M4)