Index: chrome/content/elemHideEmulation.js
===================================================================
--- a/chrome/content/elemHideEmulation.js
+++ b/chrome/content/elemHideEmulation.js
@@ -284,16 +284,22 @@
     let actualPrefix = (prefix && !incompletePrefixRegexp.test(prefix)) ?
         prefix + " " : prefix;
     for (let style of styles)
       if (regexp.test(style.style))
         for (let subSelector of style.subSelectors)
         {
           if (subSelector == "*")
             subSelector = "";
+          else
+          {
+            let idx = subSelector.lastIndexOf("::");
+            if (idx != -1)
+              subSelector = subSelector.substr(0, idx);
+          }
           yield actualPrefix + subSelector;
         }
   },
 
   *getSelectors(prefix, subtree, styles)
   {
     for (let selector of this.findPropsSelectors(styles, prefix, this._regexp))
       yield [selector, subtree];