[Fix] Deleted properties still visible in inspector (#231)

Author: PaulDemeulenaere

com.unity.visualeffectgraph/CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Target GameObject attach button does not allow attaching a valid VFX if the last selection was invalid. [Case 1312178](https://issuetracker.unity3d.com/product/unity/issues/guid/1312178/)
 - Deleting flow edge between Init and Update throw an invalid opeation exception [Case 1315593](https://issuetracker.unity3d.com/product/unity/issues/guid/1315593/)
 - Having more than five GPU Event output leads to "unexpected token 'if" at compilation [Case 1323434](https://issuetracker.unity3d.com/product/unity/issues/guid/1323434/)
+- Deleted properties still show up in the inspector [Case 1320952](https://issuetracker.unity3d.com/product/unity/issues/guid/1320952/)
 
 ## [10.4.0] - 2020-01-26
 ### Changed

com.unity.visualeffectgraph/Editor/Models/VFXGraph.cs

@@ -480,7 +480,10 @@ protected override void OnInvalidate(VFXModel model, VFXModel.InvalidationCause
 
             base.OnInvalidate(model, cause);
 
-            if (model is VFXParameter || model is VFXSlot && (model as VFXSlot).owner is VFXParameter)
+            if (model is VFXParameter    //Something changed directly on VFXParameter (e.g. exposed state boolean)
+                || model is VFXSlot && (model as VFXSlot).owner is VFXParameter //Something changed on a slot owned by a VFXParameter (e.g. the default value)
+                || cause == VFXModel.InvalidationCause.kStructureChanged //A VFXParameter could have been removed
+            )
             {
                 BuildParameterInfo();
             }