Index: lib/filterClasses.js
===================================================================
--- a/lib/filterClasses.js
+++ b/lib/filterClasses.js
@@ -803,16 +803,26 @@
 
     Object.defineProperty(
       this, "sitekeys", {value: sitekeys, enumerable: true}
     );
     return this.sitekeys;
   },
 
   /**
+   * Tests whether the filter only has a location.
+   * @return {boolean}
+   */
+  isLocationOnly()
+  {
+    return this.contentType == RegExpFilter.prototype.contentType &&
+           this.thirdParty == null && !this.domains && !this.sitekeys;
+  },
+
+  /**
    * Tests whether the URL matches this filter
    * @param {string} location URL to be tested
    * @param {number} typeMask bitmask of content / request types to match
    * @param {string} [docDomain] domain name of the document that loads the URL
    * @param {boolean} [thirdParty] should be true if the URL is a third-party
    *                               request
    * @param {string} [sitekey] public key provided by the document
    * @return {boolean} true in case of a match