diff --git a/mozilla/content/html/content/src/nsHTMLAtomList.h b/mozilla/content/html/content/src/nsHTMLAtomList.h
index 13e8a8ee004..d961a9f6459 100644
--- a/mozilla/content/html/content/src/nsHTMLAtomList.h
+++ b/mozilla/content/html/content/src/nsHTMLAtomList.h
@@ -210,6 +210,7 @@ HTML_ATOM(processingInstructionPseudo, ":-moz-pi")
 HTML_ATOM(profile, "profile")
 HTML_ATOM(prompt, "prompt")
 HTML_ATOM(radioPseudo, ":-moz-radio")
+HTML_ATOM(checkPseudo, ":-moz-checkbox")
 HTML_ATOM(readonly, "readonly")
 HTML_ATOM(rel, "rel")
 HTML_ATOM(repeat, "repeat")
diff --git a/mozilla/content/shared/public/nsHTMLAtomList.h b/mozilla/content/shared/public/nsHTMLAtomList.h
index 13e8a8ee004..d961a9f6459 100644
--- a/mozilla/content/shared/public/nsHTMLAtomList.h
+++ b/mozilla/content/shared/public/nsHTMLAtomList.h
@@ -210,6 +210,7 @@ HTML_ATOM(processingInstructionPseudo, ":-moz-pi")
 HTML_ATOM(profile, "profile")
 HTML_ATOM(prompt, "prompt")
 HTML_ATOM(radioPseudo, ":-moz-radio")
+HTML_ATOM(checkPseudo, ":-moz-checkbox")
 HTML_ATOM(readonly, "readonly")
 HTML_ATOM(rel, "rel")
 HTML_ATOM(repeat, "repeat")
diff --git a/mozilla/layout/html/base/src/nsHTMLAtomList.h b/mozilla/layout/html/base/src/nsHTMLAtomList.h
index 13e8a8ee004..d961a9f6459 100644
--- a/mozilla/layout/html/base/src/nsHTMLAtomList.h
+++ b/mozilla/layout/html/base/src/nsHTMLAtomList.h
@@ -210,6 +210,7 @@ HTML_ATOM(processingInstructionPseudo, ":-moz-pi")
 HTML_ATOM(profile, "profile")
 HTML_ATOM(prompt, "prompt")
 HTML_ATOM(radioPseudo, ":-moz-radio")
+HTML_ATOM(checkPseudo, ":-moz-checkbox")
 HTML_ATOM(readonly, "readonly")
 HTML_ATOM(rel, "rel")
 HTML_ATOM(repeat, "repeat")