GUI Error & MissingReferenceException errors are thrown on deleting Particle System child game object which is created from Particle System Editor.

Steps to repro:
1. Create a new project.
2. GameObject > Effects > Particle System.
3. Inspector > Click on Open Editor button.
4. Click on "+" in Editor.
5. Hierarchy > Expand Particle System > Delete Child Particle System game object.

Actual Result:
MissingReferenceException & GUI errors are thrown in the console.

Expected Result:
No error in the console.

Reproducible in:
2020.2.0a12, 2020.1.0b9, 2020.1.0b1.

Working Fine in:
2020.1.0a26, 2019.3.14f1.

Environment:
Occurring only on Windows 10.

Stacktrace:
MissingReferenceException: The object of type 'ParticleSystem' has been destroyed but you are still trying to access it.
Your script should either check if it is null or you should not destroy the object.
UnityEditor.ParticleSystemInspector.get_selectedInParticleSystemWindow () (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.ParticleSystemInspector.ShouldShowInspector () (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.ParticleSystemInspector.OnSceneViewGUI (UnityEditor.SceneView sceneView) (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.SceneView.CallOnSceneGUI () (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.SceneView.HandleSelectionAndOnSceneGUI () (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.SceneView.OnGUI () (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.HostView.InvokeOnGUI (UnityEngine.Rect onGUIPosition, UnityEngine.Rect viewRect) (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.DockArea.DrawView (UnityEngine.Rect viewRect, UnityEngine.Rect dockAreaRect) (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEditor.DockArea.OldOnGUI () (at <fc4b42fd40b043219efbc3f11ea9c562>:0)
UnityEngine.UIElements.IMGUIContainer.DoOnGUI (UnityEngine.Event evt, UnityEngine.Matrix4x4 parentTransform, UnityEngine.Rect clippingRect, System.Boolean isComputingLayout, UnityEngine.Rect layoutSize, System.Action onGUIHandler, System.Boolean canAffectFocus) (at <f84407eabfb74dba8357ceccfe014dd7>:0)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)

GUI Error: You are pushing more GUIClips than you are popping. Make sure they are balanced.
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&)