Issue 2816 - Partial fix for EHH button in inspector tool, preview functionality still broken

chrome/content/composer.js

Index: chrome/content/composer.js
===================================================================
--- a/chrome/content/composer.js
+++ b/chrome/content/composer.js
@@ -123,31 +123,37 @@ function TreeView_getCellProperties(row,
   this.getRowProperties(row);
 }
 
 /*********************
  * General functions *
  *********************/
 
 function init() {
-  var element = window.arguments[0];
-  doc = element.ownerDocument;
-  var wnd = doc.defaultView;
+  let node = window.arguments[0];
+  let domain = window.arguments[1];
+  if (node instanceof Node)
+  {
+    doc = node.ownerDocument;
+    domain = doc.defaultView.location.hostname;
+    nodeData = new NodeData(node);
+  }
+  else
+    nodeData = node;
 
   // Check whether element hiding group is disabled
   let subscription = AdblockPlus.getSubscription("~eh~");
   if (subscription && subscription.disabled)
   {
     let warning = document.getElementById("groupDisabledWarning");
     if (/\?1\?/.test(warning.textContent))
       warning.textContent = warning.textContent.replace(/\?1\?/g, subscription.title);
     warning.hidden = false;
   }
 
-  nodeData = new NodeData(element);
   nodeData.tagName.checked = true;
   if (nodeData.attributes.length > 0)
   {
     let maxLen = 0;
     let bestAttr = null;
     for (let i = 0; i < nodeData.attributes.length; i++)
     {
       let len = nodeData.attributes[i].value.length;
@@ -164,17 +170,16 @@ function init() {
     }
     if (bestAttr)
     {
       bestAttr.selected = bestAttr.value;
       bestAttr.checked = true;
     }
   }
 
-  let domain = wnd.location.hostname;
   let selectedDomain;
   switch (Prefs.composer_defaultDomain)
   {
     case 0:
       selectedDomain = "";
       break;
     case 1:
       try
@@ -237,17 +242,17 @@ function updateExpression()
         {
           var op = "*=";
           if (attr.selected == attr.value)
             op = "=";
           else if (attr.value.substr(0, attr.selected.length) == attr.selected)
             op = "^=";
           else if (attr.value.substr(attr.value.length - attr.selected.length) == attr.selected)
             op = "$=";
-  
+
           let useFallback = false;
           if (attr.name == "id" && op == "=")
             expression += "#" + escapeName(attr.selected).replace(/^([^a-zA-Z\\])/, escapeChar).replace(/\\(\s)$/, escapeChar);
           else if (attr.name == "class" && /\S/.test(attr.selected))
           {
             let knownClasses = new Set(attr.value.split(/\s+/));
             let classes = attr.selected.split(/\s+/).filter(cls => cls != "");
             if (classes.every(cls => knownClasses.has(cls)))