Steps to reproduce:
1. Download package [Internal link]
2. Install it into any project
3. Navigate to "Packages -> Unity Explorer -> Editor -> UI -> Scenario Builder"
4. Double-click on ScenarioBuilder.uxml to open it in UI Builder
Actual results:
The main GraphView area has zero height
Expected results:
The main GraphView area is visible (take a look into attached screenshots)
Regression in 2023.3.0b11
Tested on (OS): Windows