Issue 3448 - TypeError: this.treeElement is null error when closing Filter Preferences

chrome/content/ui/filters-filterview.js

Index: chrome/content/ui/filters-filterview.js
===================================================================
--- a/chrome/content/ui/filters-filterview.js
+++ b/chrome/content/ui/filters-filterview.js
@@ -628,45 +628,45 @@ var FilterView =
       this.boxObject.invalidateRange(Math.min(oldPosition, newPosition), Math.max(oldPosition, newPosition));
     }
   },
 
   QueryInterface: XPCOMUtils.generateQI([Ci.nsITreeView]),
 
   setTree: function(boxObject)
   {
+    if (!boxObject)
+      return;
+
     this.init();
     this.boxObject = boxObject;
 
-    if (this.boxObject)
+    this.noGroupDummy = {index: 0, filter: {text: this.boxObject.treeBody.getAttribute("noGroupText"), dummy: true}};
+    this.noFiltersDummy = {index: 0, filter: {text: this.boxObject.treeBody.getAttribute("noFiltersText"), dummy: true}};
+    this.editDummy = {filter: {text: ""}};
+
+    let atomService = Cc["@mozilla.org/atom-service;1"].getService(Ci.nsIAtomService);
+    let stringAtoms = ["col-filter", "col-enabled", "col-hitcount", "col-lasthit", "type-invalid", "type-comment", "type-blocking", "type-whitelist", "type-elemhide", "type-elemhideexception", "type-cssproperty"];
+    let boolAtoms = ["selected", "dummy", "slow", "disabled"];
+
+    this.atoms = {};
+    for (let atom of stringAtoms)
+      this.atoms[atom] = atomService.getAtom(atom);
+    for (let atom of boolAtoms)
     {
-      this.noGroupDummy = {index: 0, filter: {text: this.boxObject.treeBody.getAttribute("noGroupText"), dummy: true}};
-      this.noFiltersDummy = {index: 0, filter: {text: this.boxObject.treeBody.getAttribute("noFiltersText"), dummy: true}};
-      this.editDummy = {filter: {text: ""}};
+      this.atoms[atom + "-true"] = atomService.getAtom(atom + "-true");
+      this.atoms[atom + "-false"] = atomService.getAtom(atom + "-false");
+    }
 
-      let atomService = Cc["@mozilla.org/atom-service;1"].getService(Ci.nsIAtomService);
-      let stringAtoms = ["col-filter", "col-enabled", "col-hitcount", "col-lasthit", "type-invalid", "type-comment", "type-blocking", "type-whitelist", "type-elemhide", "type-elemhideexception", "type-cssproperty"];
-      let boolAtoms = ["selected", "dummy", "slow", "disabled"];
+    let columns = this.boxObject.columns;
+    for (let i = 0; i < columns.length; i++)
+      if (columns[i].element.hasAttribute("sortDirection"))
+        this.sortBy(columns[i].id, columns[i].element.getAttribute("sortDirection"));
 
-      this.atoms = {};
-      for (let atom of stringAtoms)
-        this.atoms[atom] = atomService.getAtom(atom);
-      for (let atom of boolAtoms)
-      {
-        this.atoms[atom + "-true"] = atomService.getAtom(atom + "-true");
-        this.atoms[atom + "-false"] = atomService.getAtom(atom + "-false");
-      }
-
-      let columns = this.boxObject.columns;
-      for (let i = 0; i < columns.length; i++)
-        if (columns[i].element.hasAttribute("sortDirection"))
-          this.sortBy(columns[i].id, columns[i].element.getAttribute("sortDirection"));
-
-      this.refresh(true);
-    }
+    this.refresh(true);
 
     // Stop propagation of keypress events so that these aren't intercepted by
     // the findbar.
     this.treeElement.inputField.addEventListener("keypress", event => {
       event.stopPropagation();
     }, false);
   },