Steps to reproduce:
- Create a new project that includes HDRP with Unity 2018.1 (either using HDRP template, 2018.1 branch of the repository https://github.com/Unity-Technologies/ScriptableRenderPipeline/tree/2018.1 , or adding the HDRP package in an empty project)
- Remove any RenderPipelineAsset assigned in the graphic settings
- Create a new Reflection Probe (Game Object -> Light -> Reflection Probe)

Expected: New reflection probe is added with no error

Result: Following error is thrown at every frame :
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NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Experimental.Rendering.HDReflectionProbeEditor.Gizmos_Influence (UnityEngine.ReflectionProbe p, UnityEngine.Experimental.Rendering.HDAdditionalReflectionData a, UnityEditor.Editor e, Boolean isEdit) (at C:/Users/Remy/AppData/Local/Unity/cache/packages/packages.unity.com/com.unity.render-pipelines.high-definition@1.1.4-preview/HDRP/Editor/Lighting/Reflection/HDReflectionProbeEditor.Handles.cs:399)
UnityEditor.Experimental.Rendering.HDReflectionProbeEditor.DrawSelectedGizmo (UnityEngine.ReflectionProbe reflectionProbe, GizmoType gizmoType) (at C:/Users/Remy/AppData/Local/Unity/cache/packages/packages.unity.com/com.unity.render-pipelines.high-definition@1.1.4-preview/HDRP/Editor/Lighting/Reflection/HDReflectionProbeEditor.Handles.cs:320)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)
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