How to reproduce:
1. Change the Decimal symbol in your OS to ',' (comma)
2. Open the attached '1299536.zip' project
3. In the Project window double-click on the 'Test' Asset
4. Expand the Code Preview pane (located at the bottom of the UI Builder window)
5. In the Hierarchy of the UI Builder expand 'Test' and select 'Visual Element'
6. Resize Visual Element by dragging one of its sides
7. Observe the height and width of the Visual Element displayed in the Code Preview Pane

Expected result: The '.' (dot) character is not used as the thousands separator
Actual result: The '.' (dot) character is used as the thousands separator

Reproducible with: UI Builder 1.0.0-preview.4, 1.0.0-preview.11 (2019.4.17f1, 2020.1.17f1, 2020.2.0f1), 1.0.0-preview.11 (2021.1.0a10)
Cannot test with: 2018.4.30f1 (The UI Builder package versions are not supported), UI Builder 1.0.0-preview.4 (2021.1.0a10) (due to errors)

Notes:
- The issue does not reproduce when height and width are set in the UI Builder Inspector