Issue 4536 - Make sure the elements stay hidden after adding the filter

chrome/content/composer.js

 /*
  * This Source Code is subject to the terms of the Mozilla Public License
  * version 2.0 (the "License"). You can obtain a copy of the License at
  * http://mozilla.org/MPL/2.0/.
  */
 
 let {Prefs} = require("prefs");
 
 let domainData;
 let nodeData;
 let nodeID;
 let selectedNode = null;
 var advancedMode = false;
 let treeView = null;
+let ruleAdded = false;
 let stylesheetData;
-let previewStyle = null;

[saroyanm, 2016/10/17 14:41:44]

I assume it's irrelevant to the review, but redundant variable.

[Wladimir Palant, 2016/10/17 14:51:29]

Yes, became redundant due to E10S adjustments and was overlooked apparently.

 
 let abpURL = Cc["@adblockplus.org/abp/public;1"].getService(Ci.nsIURI);
 Cu.import(abpURL.spec);
 
 /*******************
  * TreeView object *
  *******************/
 
 function TreeView(tree) {
   var origView = tree.view;
@@ skipping 537 matching lines @@
                  .getItemAtIndex(min.value);
   if (!item || !item.nodeData)
     return;
 
   fillAttributes(item.nodeData);
 }
 
 function addExpression()
 {
   AdblockPlus.addPatterns([document.getElementById("expression").value]);
+  ruleAdded = true;
+}
 
-  togglePreview(false);
-}
+window.addEventListener("unload", () =>
+{
+  togglePreview(ruleAdded, true);
+});