How to reproduce:
1. Open the “UIToolkitBugsBundle.zip“ project
2. Open the “UI Document“ in UI Builder
3. In the StyleSheet tab, create a selector named "1style" or just "9" (first character being any number)
4. Select the new selector and press CTRL + D
5. Observe the StyleSheets tab

Expected result: Duplicated selector is identical to, or is renamed to a variant of, the original name
Actual result: Duplicated selector is renamed to an asterisk ("")

Reproducible in: 2022.1.0a1, 2022.3.62f1, 6000.0.49f1, 6000.1.3f1, 6000.2.0b1

Reproduced on: Windows 11 Pro (24H2)
Not reproduced on: No other environment tested

Notes:
- If the name features a number but does not start with it, the duplicated selector will be an identical copy of the original one
- Sometimes when opening the UIDocument or restarting the project, the non-duplicated names (starting with numbers) will become an astersik(““)