Got the same (Unity 2019.4.22f1) found a working temporary fix:
Look at the code added by // SDP tag
ObiActorBluePrintEditor.cs
Selectable.cs (in Unity source code Unity.app/Contents/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/UI/Core/Selectable.cs)
Can be useful if upgrading your Unity is not an option
Look at the code added by // SDP tag
ObiActorBluePrintEditor.cs
Selectable.cs (in Unity source code Unity.app/Contents/Resources/PackageManager/BuiltInPackages/com.unity.ugui/Runtime/UI/Core/Selectable.cs)
Can be useful if upgrading your Unity is not an option