diff --git a/src/Reveal.Sdk.Dom/Data/Enums/DataSourceProvider.cs b/src/Reveal.Sdk.Dom/Data/Enums/DataSourceProvider.cs
index a1c468b0..cad78b12 100644
--- a/src/Reveal.Sdk.Dom/Data/Enums/DataSourceProvider.cs
+++ b/src/Reveal.Sdk.Dom/Data/Enums/DataSourceProvider.cs
@@ -25,6 +25,9 @@ public enum DataSourceProvider
         [EnumMember(Value = "DROPBOXPROVIDER")]
         Dropbox,
 
+        [EnumMember(Value = "GOOGLE_ADS")]
+        GoogleAds,
+
         [EnumMember(Value = "GOOGLE_ANALYTICS")]
         GoogleAnalytics,
 
diff --git a/src/Reveal.Sdk.Dom/Visualizations/GridVisualization.cs b/src/Reveal.Sdk.Dom/Visualizations/GridVisualization.cs
index b1b7a1b7..eacb0e89 100644
--- a/src/Reveal.Sdk.Dom/Visualizations/GridVisualization.cs
+++ b/src/Reveal.Sdk.Dom/Visualizations/GridVisualization.cs
@@ -27,9 +27,18 @@ public GridVisualization(DataSourceItem dataSourceItem) : this(null, dataSourceI
         public GridVisualization(string title, DataSourceItem dataSourceItem) : base(title, dataSourceItem) { ChartType = ChartType.Grid; }
 
         [JsonIgnore]
-        public List<TabularColumn> Columns { get { return VisualizationDataSpec.Columns; } }
+        public List<TabularColumn> Columns { get {
+                if (VisualizationDataSpec is GridVisualizationDataSpec gds)
+                {
+                    return gds.Columns;
+                }
+                else 
+                {
+                    return new List<TabularColumn>();
+                }
+            } }
 
         [JsonProperty(Order = 7)]
-        GridVisualizationDataSpec VisualizationDataSpec { get; set; } = new GridVisualizationDataSpec();
+        VisualizationDataSpec VisualizationDataSpec { get; set; } = new GridVisualizationDataSpec();
     }
 }