diff --git a/browser/base/content/browser-context.inc b/browser/base/content/browser-context.inc
index fa8b3a7ba900..bbec2bb86fc2 100644
--- a/browser/base/content/browser-context.inc
+++ b/browser/base/content/browser-context.inc
@@ -54,7 +54,7 @@
                 label="&openLinkCmdInCurrent.label;"
                 accesskey="&openLinkCmdInCurrent.accesskey;"
                 oncommand="gContextMenu.openLinkInCurrent();"/>
-# label and usercontextid are dynamically set.
+# label and data-usercontextid are dynamically set.
       <menuitem id="context-openlinkincontainertab"
                 accesskey="&openLinkCmdInTab.accesskey;"
                 oncommand="gContextMenu.openLinkInTab(event);"/>
diff --git a/browser/base/content/nsContextMenu.js b/browser/base/content/nsContextMenu.js
index 0e842d41c480..5ad58a89bd14 100644
--- a/browser/base/content/nsContextMenu.js
+++ b/browser/base/content/nsContextMenu.js
@@ -151,7 +151,7 @@ nsContextMenu.prototype = {
       inContainer = true;
       var item = document.getElementById("context-openlinkincontainertab");
 
-      item.setAttribute("usercontextid", userContextId);
+      item.setAttribute("data-usercontextid", userContextId);
 
       var label = ContextualIdentityService.getUserContextLabel(userContextId);
       item.setAttribute("label",
@@ -1008,7 +1008,7 @@ nsContextMenu.prototype = {
 
     let params = {
       allowMixedContent: persistAllowMixedContentInChildTab,
-      userContextId: parseInt(event.target.getAttribute('usercontextid'))
+      userContextId: parseInt(event.target.getAttribute('data-usercontextid')),
     };
 
     openLinkIn(this.linkURL, "tab", this._openLinkInParameters(params));