--- a/browser/components/extensions/ext-browserAction.js
+++ b/browser/components/extensions/ext-browserAction.js
@@ -316,17 +316,17 @@ this.browserAction = class extends Exten
    */
   getPopup(window, popupURL, blockParser = false) {
     this.clearPopupTimeout();
     let {pendingPopup} = this;
     this.pendingPopup = null;
 
     if (pendingPopup) {
       if (pendingPopup.window === window && pendingPopup.popupURL === popupURL) {
-        if (!this.blockParser) {
+        if (!blockParser) {
           pendingPopup.unblockParser();
         }
 
         return pendingPopup;
       }
       pendingPopup.destroy();
     }