Revert ab29ec8: container==content auto-fit made it worse — back to alpha-crop with the container at element size

The container tracks the element's own Width/Height again; the crop stays in the bitmap.

ViewModels/MainViewModel.cs

@@ -2290,11 +2290,6 @@ public class MainViewModel : ViewModelBase
         _ = RedesignateBackgroundAsync($"{MonitorKeyPrefix}{display.Index}");
     }
 
-    // True while the user is dragging/resizing an element on the preview canvas
-    // (set by MainWindow code-behind). Suppresses the web source's auto-fit so it
-    // doesn't fight the gesture mid-drag.
-    public bool IsPreviewDragging { get; set; }
-
     public void InitWebView2(Panel hostPanel)
     {
         _webView2Manager = new WebView2Manager(hostPanel, System.Windows.Application.Current.Dispatcher);
@@ -2302,26 +2297,11 @@ public class MainViewModel : ViewModelBase
         RegisterLoadedWebSources();
     }
 
-    private void OnWebView2PreviewBitmapChanged(string sourceId, WriteableBitmap bitmap, double canvasW, double canvasH)
+    private void OnWebView2PreviewBitmapChanged(string sourceId, WriteableBitmap bitmap)
     {
         foreach (var scene in Scenes)
             foreach (var el in scene.Elements.OfType<Source>().Where(s => s.Id == sourceId))
-            {
                 el.VideoImageSource = bitmap;
-
-                // The container must equal the content: size the element grid
-                // (and therefore the selection box) to the cropped frame's canvas
-                // extent. Skipped while the user is dragging/resizing the element
-                // so the gesture isn't fought mid-drag.
-                if (IsPreviewDragging || canvasW < 1 || canvasH < 1) continue;
-                var w = Math.Clamp(Math.Round(canvasW), 1, 1920);
-                var h = Math.Clamp(Math.Round(canvasH), 1, 1080);
-                if (Math.Abs(el.Width - w) > 1 || Math.Abs(el.Height - h) > 1)
-                {
-                    el.Width = w;
-                    el.Height = h;
-                }
-            }
     }
 
     public void Shutdown()