Description

The code accesses MainWindow.unityInstallationsSource without checking if it's null. This can cause a NullReferenceException when the window is opened before the main window has initialized the data source, leading to a crash.

Severity: medium
File: UnityLauncherPro/UpgradeWindow.xaml.cs

Expected Behavior

The code should handle this case properly to avoid unexpected errors or degraded quality.