Console gets spammed with:

The targets array should not be used inside OnSceneGUI or OnPreviewGUI. Use the single target property instead.
UnityEditor.DockArea:OnGUI()

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.RectTransformEditor.GetAnchorLocal (UnityEngine.RectTransform guiParent, Vector2 anchor) (at C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/Inspector/RectTransformEditor.cs:777)
UnityEditor.RectTransformEditor.DrawAnchorRect (UnityEngine.Transform parentSpace, UnityEngine.RectTransform gui, UnityEngine.RectTransform guiParent, Int32 axis) (at C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/Inspector/RectTransformEditor.cs:1061)
UnityEditor.RectTransformEditor.DrawSizes (Rect rectInUserSpace, UnityEngine.Transform userSpace, Rect rectInParentSpace, UnityEngine.Transform parentSpace, UnityEngine.RectTransform gui, UnityEngine.RectTransform guiParent) (at C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/Inspector/RectTransformEditor.cs:910)
UnityEditor.RectTransformEditor.OnSceneGUI () (at C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/Inspector/RectTransformEditor.cs:548)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.SceneView.CallOnSceneGUI () (at C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/SceneView/SceneView.cs:1674)
UnityEditor.SceneView.HandleSelectionAndOnSceneGUI () (at C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/SceneView/SceneView.cs:1093)
UnityEditor.SceneView.OnGUI () (at C:/BuildAgent/work/afa2580bf6048259/Editor/Mono/SceneView/SceneView.cs:970)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/monoAndRuntimeClassLibs/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)