Clicking "-" or "+" in UI Builder's "Inlined Styles" Variables automatically selects a variable that was previously deselected

How to reproduce:
1. Create a new Unity project
2. In the Project window, right-click -> Create -> UI Toolkit -> UI Builder -> Open the created Asset
3. Add the Visual Element into the UI Builder's Hierarchy and select it
4. In the UI Builder's Inspector, go to Inlined Styles -> Variables -> + -> Add a few variables and select one of them
5. Make sure to deselect the variables and click the "-" button
6. Observe the results

Expected results: The last item on the list is removed since nothing is selected
Actual results: The previously selected variable is removed even though it was deselected

Reproducible with: 6000.6.0a2
Can't test with: 6000.0.71f1, 6000.3.12f1, 6000.4.2f1, 6000.5.0b2 (No variables)

Reproducible on: macOS Tahoe 26 (M1) 
Not reproducible on: No other environment tested