fixed stacking order issue when resizing notes

Former-commit-id: 7c7cd2088caa48fc9faaaf79a79d41edf07de937

extension/ui/pages/editor-frame-web.css

@@ -23,6 +23,10 @@
     color: inherit !important;
 }
 
+.single-file-mask {
+    opacity: .99 !important;
+}
+
 single-file-note {
     all: initial !important;
 }