diff --git a/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs b/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs
index b9b85587aa..3275575ca0 100644
--- a/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs
+++ b/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs
@@ -328,7 +328,7 @@ namespace OpenRA.Mods.Common.Traits
 
 		public EditorActorPreview this[string id]
 		{
-			get { return previews.FirstOrDefault(p => p.ID.ToLowerInvariant() == id); }
+			get { return previews.FirstOrDefault(p => p.ID.Equals(id, StringComparison.OrdinalIgnoreCase)); }
 		}
 	}
 }
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Editor/ActorEditLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Editor/ActorEditLogic.cs
index 9d1b1553d7..22c837bc8f 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Editor/ActorEditLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Editor/ActorEditLogic.cs
@@ -126,11 +126,13 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				}
 
 				// Check for duplicate actor ID
-				if (CurrentActor.ID.Equals(actorId, StringComparison.OrdinalIgnoreCase))
+				if (!CurrentActor.ID.Equals(actorId, StringComparison.OrdinalIgnoreCase))
 				{
 					if (editorActorLayer[actorId] != null)
 					{
 						nextActorIDStatus = ActorIDStatus.Duplicate;
+						actorIDErrorLabel.Text = "Duplicate ActorID";
+						actorIDErrorLabel.Visible = true;
 						return;
 					}
 				}