Picom transparency hide stacked windows

picom.nix

@@ -12,6 +12,9 @@
         "window_type = 'dock'"
         "window_type = 'desktop'"
       ];
+      opacity-rule = [
+        "0:_NET_WM_STATE@:32a *= '_NET_WM_STATE_HIDDEN'"
+      ];
     };
   };
 }