--- a/toolkit/.eslintrc
+++ b/toolkit/.eslintrc
@@ -57,17 +57,17 @@
 
     // No duplicate keys in object declarations
     "no-dupe-keys": 2,
 
     // No duplicate cases in switch statements
     "no-duplicate-case": 2,
 
     // No labels
-    // "no-labels": 2,
+    "no-labels": 2,
 
     // If an if block ends with a return no need for an else block
     // "no-else-return": 2,
 
     // No empty statements
     // "no-empty": 2,
 
     // No empty character classes in regex
@@ -81,17 +81,17 @@
 
     // No using !! where casting to boolean is already happening
     // "no-extra-boolean-cast": 2,
 
     // No double semicolon
     "no-extra-semi": 2,
 
     // No overwriting defined functions
-    // "no-func-assign": 2,
+    "no-func-assign": 2,
 
     // No invalid regular expresions
     "no-invalid-regexp": 2,
 
     // No odd whitespace characters
     "no-irregular-whitespace": 2,
 
     // No single if block inside an else block
@@ -99,20 +99,20 @@
 
     // No mixing spaces and tabs in indent
     "no-mixed-spaces-and-tabs": [2, "smart-tabs"],
 
     // No unnecessary spacing
     // "no-multi-spaces": [2, { exceptions: { "AssignmentExpression": true, "VariableDeclarator": true, "ArrayExpression": true, "ObjectExpression": true } }],
 
     // No reassigning native JS objects
-    // "no-native-reassign": 2,
+    "no-native-reassign": 2,
 
     // No (!foo in bar)
-    // "no-negated-in-lhs": 2,
+    "no-negated-in-lhs": 2,
 
     // Nested ternary statements are confusing
     // "no-nested-ternary": 2,
 
     // Use {} instead of new Object()
     // "no-new-object": 2,
 
     // No Math() or JSON()

--- a/toolkit/components/asyncshutdown/AsyncShutdown.jsm
+++ b/toolkit/components/asyncshutdown/AsyncShutdown.jsm
@@ -173,17 +173,17 @@ PromiseSet.prototype = {
     value.resolve();
     return true;
   },
 
   _ensurePromise: function(key) {
     if (!key || typeof key != "object") {
       throw new Error("Expected an object");
     }
-    if ((!"then" in key) || typeof key.then != "function") {
+    if ((!("then" in key)) || typeof key.then != "function") {
       throw new Error("Expected a Promise");
     }
   },
 
 };
 
 
 /**

--- a/toolkit/components/formautofill/FormAutofillStartup.js
+++ b/toolkit/components/formautofill/FormAutofillStartup.js
@@ -44,17 +44,17 @@ FormAutofillStartup.prototype = {
   },
 
   // nsIFrameMessageListener
   receiveMessage: function (aMessage) {
     // Process the "FormAutofill:RequestAutocomplete" message.  Any exception
     // raised in the parent process is caught and serialized into the reply
     // message that is sent to the requesting child process.
     FormAutofill.processRequestAutocomplete(aMessage.data)
-      .catch(ex => { exception: ex })
+      .catch(ex => { return { exception: ex } })
       .then(result => {
         // The browser message manager in the parent will send the reply to the
         // associated frame message manager in the child.
         let browserMM = aMessage.target.messageManager;
         browserMM.sendAsyncMessage("FormAutofill:RequestAutocompleteResult",
                                    result);
       })
       .catch(Cu.reportError);

--- a/toolkit/content/widgets/toolbar.xml
+++ b/toolkit/content/widgets/toolbar.xml
@@ -237,37 +237,42 @@
             var paletteChildren = palette ? palette.childNodes : [];
             for (let c = 0; c < paletteChildren.length; c++) {
               let curNode = paletteChildren[c];
               paletteItems[curNode.id] = curNode;
             }
 
             var children = this.childNodes;
 
-            iter:
             // iterate over the ids to use on the toolbar
             for (let i = 0; i < ids.length; i++) {
-              let  id = ids[i];
+              let id = ids[i];
               // iterate over the existing nodes on the toolbar. nodeidx is the
               // spot where we want to insert items.
+              let found = false;
               for (let c = nodeidx; c < children.length; c++) {
                 let curNode = children[c];
                 if (this._idFromNode(curNode) == id) {
                   // the node already exists. If c equals nodeidx, we haven't
                   // iterated yet, so the item is already in the right position.
                   // Otherwise, insert it here.
                   if (c != nodeidx) {
                     this.insertBefore(curNode, children[nodeidx]);
                   }
 
                   added[curNode.id] = true;
                   nodeidx++;
-                  continue iter; // move on to the next id
+                  found = true;
+                  break;
                 }
               }
+              if (found) {
+                // move on to the next id
+                continue;
+              }
 
               // the node isn't already on the toolbar, so add a new one.
               var nodeToAdd = paletteItems[id] || this._getToolbarItem(id);
               if (nodeToAdd && !(nodeToAdd.id in added)) {
                 added[nodeToAdd.id] = true;
                 this.insertBefore(nodeToAdd, children[nodeidx] || null);
                 nodeToAdd.setAttribute("removable", "true");
                 nodeidx++;

--- a/toolkit/modules/secondscreen/SimpleServiceDiscovery.jsm
+++ b/toolkit/modules/secondscreen/SimpleServiceDiscovery.jsm
@@ -189,17 +189,17 @@ var SimpleServiceDiscovery = {
 
     if (!fixedDevices) {
       return;
     }
 
     fixedDevices = JSON.parse(fixedDevices);
     for (let fixedDevice of fixedDevices) {
       // Verify we have the right data
-      if (!"location" in fixedDevice || !"target" in fixedDevice) {
+      if (!("location" in fixedDevice) || !("target" in fixedDevice)) {
         continue;
       }
 
       fixedDevice.location = this._forceTrailingSlash(fixedDevice.location);
 
       let service = {
         location: fixedDevice.location,
         target: fixedDevice.target