diff --git a/mangle.json b/mangle.json
index 26be490c61..cf506a61e8 100644
--- a/mangle.json
+++ b/mangle.json
@@ -39,6 +39,7 @@
       "$_depth": "__b",
       "$_nextDom": "__d",
       "$_dirty": "__d",
+      "$_mask": "__m",
       "$_detachOnNextRender": "__b",
       "$_force": "__e",
       "$_nextState": "__s",