To reproduce:
1. Open attached project
2. Enter Play Mode
3. Open Entity Debugger
4. Select Entity 0

Expected results: no errors
Actual results: these errors are received:
ArgumentException: GetComponentDataRaw<WobblerComponent> can not be called with a zero sized component.
Unity.Entities.EntityManager.GetComponentDataRawRW (Unity.Entities.Entity entity, System.Int32 typeIndex) (at Library/PackageCache/com.unity.entities@0.0.12-preview.19/Unity.Entities/EntityManager.cs:744)
Unity.Entities.Properties.EntityContainer+ReadOnlyComponentsProperty.Get (Unity.Entities.Properties.EntityContainer& container, System.Int32 index, System.Collections.Generic.HashSet`1[T] primitiveTypes) (at Library/PackageCache/com.unity.entities@0.0.12-preview.19/Unity.Entities.Properties/EntityContainer.cs:121)
Unity.Entities.Properties.EntityContainer+ReadOnlyComponentsProperty.Accept (Unity.Entities.Properties.EntityContainer& container, Unity.Properties.IPropertyVisitor visitor) (at Library/PackageCache/com.unity.entities@0.0.12-preview.19/Unity.Entities.Properties/EntityContainer.cs:46)
Unity.Properties.StructPropertyBag`1[TContainer].Visit (TContainer& container, Unity.Properties.IPropertyVisitor visitor) (at Library/PackageCache/com.unity.properties@0.2.11-preview/Unity.Properties/PropertyBag.cs:196)
Unity.Entities.Editor.EntitySelectionProxyEditor.OnInspectorGUI () (at Library/PackageCache/com.unity.entities@0.0.12-preview.19/Unity.Entities.Editor/EntityDebugger/EntitySelectionProxyEditor.cs:37)
UnityEditor.InspectorWindow.DoOnInspectorGUI (System.Boolean rebuildOptimizedGUIBlock, UnityEditor.Editor editor, System.Boolean wasVisible, UnityEngine.Rect& contentRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1608)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Reproducible with: 2018.3.1f1, 2019.1.0a13