How to reproduce:
1. Import the attached script "NewEmptyCSharpScript"
2. Assets > Create > MyGraph
3. In the Blackboard, press the "+" button to add a variable multiple times
4. Repeat step 3 until the variable list is taller than the Blackboard panel
5. Observe the results
Expected results: The "Blackboard" header stays fully visible and the variable rows are clipped below it
Actual results: The variable rows render over the "Blackboard" header and partially cover its icon and label
Reproducible with: 6000.7.0a5
Reproducible on: macOS Tahoe 26 (M1)
Not reproducible on: 6000.5.0f1