diff --git a/Models/SceneElement.cs b/Models/SceneElement.cs
index d5b438d..8b196de 100644
--- a/Models/SceneElement.cs
+++ b/Models/SceneElement.cs
@@ -56,6 +56,9 @@ public abstract class SceneElement : INotifyPropertyChanged
     /// <summary>True only for image sources — the raw preview renderer's discriminator.</summary>
     public virtual bool IsImageSource => false;
 
+    /// <summary>True only for ChatBox-type sources. Gates chat overlay properties panel.</summary>
+    public virtual bool IsChatBox => false;
+
     private bool _isVisible = true;
     public bool IsVisible { get => _isVisible; set => Set(ref _isVisible, value); }
 
diff --git a/Models/Source.cs b/Models/Source.cs
index 73bb98a..34feea0 100644
--- a/Models/Source.cs
+++ b/Models/Source.cs
@@ -182,7 +182,7 @@ public class Source : SceneElement
         set => Set(ref _chatFadeSeconds, Math.Clamp(value, 0, 60));
     }
 
-    public bool IsChatBox => Type == SourceType.ChatBox;
+    public override bool IsChatBox => Type == SourceType.ChatBox;
 
     private bool _chatPreviewEnabled = true;
     public bool ChatPreviewEnabled