diff --git a/SourceGen/WpfGui/EditBitmapAnimation.xaml b/SourceGen/WpfGui/EditBitmapAnimation.xaml
index 44b8793..efcd752 100644
--- a/SourceGen/WpfGui/EditBitmapAnimation.xaml
+++ b/SourceGen/WpfGui/EditBitmapAnimation.xaml
@@ -73,7 +73,7 @@ limitations under the License.
                       AutoGenerateColumns="False"
                       HeadersVisibility="Column"
                       CanUserReorderColumns="False"
-                      SelectionMode="Single"
+                      SelectionMode="Extended"
                       SelectionChanged="VisSourceGrid_SelectionChanged"
                       MouseDoubleClick="VisSourceGrid_MouseDoubleClick">
                 <DataGrid.Resources>
diff --git a/SourceGen/WpfGui/EditBitmapAnimation.xaml.cs b/SourceGen/WpfGui/EditBitmapAnimation.xaml.cs
index 586a0b8..f3432ea 100644
--- a/SourceGen/WpfGui/EditBitmapAnimation.xaml.cs
+++ b/SourceGen/WpfGui/EditBitmapAnimation.xaml.cs
@@ -178,9 +178,7 @@ namespace SourceGen.WpfGui {
                         // disallow using animations as animation frames
                         continue;
                     }
-                    if (!VisAnimItems.Contains(vis)) {
-                        VisSourceItems.Add(vis);
-                    }
+                    VisSourceItems.Add(vis);
                 }
             }
 
@@ -192,6 +190,15 @@ namespace SourceGen.WpfGui {
             }
         }
 
+        // Want to focus on the first item, not the grid.  Probably need a hack like
+        // MainWindow's ItemContainerGenerator_StatusChanged.  Not really worth it here.
+        //private void Window_ContentRendered(object sender, EventArgs e) {
+        //    visSourceGrid.Focus();
+        //    DataGridRow dgr =
+        //        (DataGridRow)visSourceGrid.ItemContainerGenerator.ContainerFromIndex(0);
+        //    dgr.Focus();
+        //}
+
         private void Window_Closing(object sender, CancelEventArgs e) {
             previewAnim.Stop();
         }
@@ -233,6 +240,8 @@ namespace SourceGen.WpfGui {
                 visAnimGrid.SelectedIndex != VisAnimItems.Count - 1;
             IsPreviewEnabled = VisAnimItems.Count > 0;
 
+            IsValid &= IsPreviewEnabled;    // don't allow animations with no frames
+
             string trimTag = Visualization.TrimAndValidateTag(TagString, out bool tagOk);
             Visualization match =
                 EditVisualizationSet.FindVisualizationByTag(mEditedList, trimTag);
@@ -276,26 +285,17 @@ namespace SourceGen.WpfGui {
         }
 
         /// <summary>
-        /// Adds an item to the animation list, moving it from the source list.
+        /// Adds an item to the animation list.
         /// </summary>
         private void AddSelection() {
             if (!IsAddEnabled) {
                 return;
             }
 
-            Visualization item = (Visualization)visSourceGrid.SelectedItem;
-            int index = VisSourceItems.IndexOf(item);
-            Debug.Assert(index >= 0);
-            VisSourceItems.Remove(item);
-            VisAnimItems.Add(item);
-
-            if (index == VisSourceItems.Count) {
-                index--;
+            for (int i = 0; i < visSourceGrid.SelectedItems.Count; i++) {
+                Visualization item = (Visualization)visSourceGrid.SelectedItems[i];
+                VisAnimItems.Add(item);
             }
-            if (index >= 0) {
-                visSourceGrid.SelectedIndex = index;
-            }
-
             if (visAnimGrid.SelectedIndex < 0) {
                 visAnimGrid.SelectedIndex = 0;
             }
@@ -304,18 +304,16 @@ namespace SourceGen.WpfGui {
         }
 
         /// <summary>
-        /// Removes an item from the animation list, moving it to the source list.
+        /// Removes an item from the animation list.
         /// </summary>
         private void RemoveSelection() {
             if (!IsRemoveEnabled) {
                 return;
             }
 
-            Visualization item = (Visualization)visAnimGrid.SelectedItem;
-            int index = VisAnimItems.IndexOf(item);
+            int index = visAnimGrid.SelectedIndex;
             Debug.Assert(index >= 0);
-            VisAnimItems.Remove(item);
-            VisSourceItems.Add(item);
+            VisAnimItems.RemoveAt(index);
 
             if (index == VisAnimItems.Count) {
                 index--;
@@ -324,10 +322,6 @@ namespace SourceGen.WpfGui {
                 visAnimGrid.SelectedIndex = index;
             }
 
-            if (visSourceGrid.SelectedIndex < 0) {
-                visSourceGrid.SelectedIndex = 0;
-            }
-
             RefreshAnim();
         }
 
@@ -337,15 +331,7 @@ namespace SourceGen.WpfGui {
         private void ClearButton_Click(object sender, RoutedEventArgs e) {
             Debug.Assert(IsRemoveEnabled);
 
-            while (VisAnimItems.Count > 0) {
-                Visualization item = VisAnimItems[0];
-                VisAnimItems.Remove(item);
-                VisSourceItems.Add(item);
-            }
-
-            if (visSourceGrid.SelectedIndex < 0) {
-                visSourceGrid.SelectedIndex = 0;
-            }
+            VisAnimItems.Clear();
 
             RefreshAnim();
         }