Copy Liron's fix

React/Views/RCTView.m

@@ -716,6 +716,21 @@ RCT_NOT_IMPLEMENTED(-(instancetype)initWithCoder : unused)
 #endif // TODO(macOS GH#774)
 
 #if TARGET_OS_OSX // [TODO(macOS GH#774)
+- (NSShadow*)shadow {
+  CALayer *layer = self.layer;
+
+  // Workaround AppKit issue with directly manipulating the view layer's shadow.
+  if (layer.shadowColor != nil && layer.shadowOpacity > 0) {
+    NSShadow *shadow = [NSShadow new];
+
+    shadow.shadowColor = [NSColor colorWithCGColor:layer.shadowColor];
+    shadow.shadowOffset = layer.shadowOffset;
+    shadow.shadowBlurRadius = layer.shadowRadius;
+
+    return shadow;
+  }
+  return nil;
+}
 - (void)viewDidMoveToWindow
 {
   // Subscribe to view bounds changed notification so that the view can be notified when a