diff --git a/browser/base/content/sanitize.js b/browser/base/content/sanitize.js
index 8107906b985..cf603d5aa24 100644
--- a/browser/base/content/sanitize.js
+++ b/browser/base/content/sanitize.js
@@ -524,6 +524,20 @@ Sanitizer.prototype = {
         let features = "chrome,all,dialog=no," + this.privateStateForNewWindow;
         let newWindow = existingWindow.openDialog("chrome://browser/content/", "_blank",
                                                   features, defaultArgs);
+#ifdef XP_MACOSX
+        function onFullScreen(e) {
+          newWindow.removeEventListener("fullscreen", onFullScreen);
+          let docEl = newWindow.document.documentElement;
+          let sizemode = docEl.getAttribute("sizemode");
+          if (!newWindow.fullScreen && sizemode == "fullscreen") {
+            docEl.setAttribute("sizemode", "normal");
+            e.preventDefault();
+            e.stopPropagation();
+            return false;
+          }
+        }
+        newWindow.addEventListener("fullscreen", onFullScreen);
+#endif
 
         // Window creation and destruction is asynchronous. We need to wait
         // until all existing windows are fully closed, and the new window is
@@ -537,6 +551,9 @@ Sanitizer.prototype = {
             return;
 
           Services.obs.removeObserver(onWindowOpened, "browser-delayed-startup-finished");
+#ifdef XP_MACOSX
+          newWindow.removeEventListener("fullscreen", onFullScreen);
+#endif
           newWindowOpened = true;
           // If we're the last thing to happen, invoke callback.
           if (numWindowsClosing == 0)
diff --git a/browser/components/customizableui/test/browser.ini b/browser/components/customizableui/test/browser.ini
index 00a09c2d538..98a4f9e9cc7 100644
--- a/browser/components/customizableui/test/browser.ini
+++ b/browser/components/customizableui/test/browser.ini
@@ -1,5 +1,5 @@
 [DEFAULT]
-skip-if = buildapp == "mulet" || e10s
+skip-if = buildapp == "mulet"
 support-files =
   head.js
   support/test_967000_charEncoding_page.html
@@ -34,6 +34,7 @@ skip-if = os == "mac"
 skip-if = os == "linux"
 
 [browser_901207_searchbar_in_panel.js]
+skip-if = e10s # bug 1090656
 [browser_913972_currentset_overflow.js]
 skip-if = os == "linux"
 
@@ -54,7 +55,6 @@ skip-if = os == "mac"
 skip-if = os == "linux"
 
 [browser_934951_zoom_in_toolbar.js]
-skip-if = e10s # Bug ?????? - test uses promiseTabLoadEvent() which isn't e10s friendly.
 [browser_938980_navbar_collapsed.js]
 [browser_938995_indefaultstate_nonremovable.js]
 [browser_940013_registerToolbarNode_calls_registerArea.js]
@@ -83,7 +83,7 @@ skip-if = os == "linux" # Intermittent failures
 [browser_947914_button_paste.js]
 skip-if = os == "linux" # Intermittent failures
 [browser_947914_button_print.js]
-skip-if = os == "linux" # Intermittent failures
+skip-if = os == "linux" || (os == "win" && e10s) # Intermittent failures on Linux, e10s issues on Windows (bug 1088714)
 [browser_947914_button_savePage.js]
 skip-if = os == "linux" # Intermittent failures
 [browser_947914_button_zoomIn.js]
@@ -100,11 +100,9 @@ skip-if = os == "linux" # Intermittent failures
 [browser_962884_opt_in_disable_hyphens.js]
 [browser_963639_customizing_attribute_non_customizable_toolbar.js]
 [browser_967000_button_charEncoding.js]
-skip-if = e10s # Bug ?????? - test uses promiseTabLoadEvent() which isn't e10s friendly.
+skip-if = e10s # Bug 1088710
 [browser_967000_button_feeds.js]
-skip-if = buildapp == 'mulet' || e10s # Bug ?????? - test uses promiseTabLoadEvent() which isn't e10s friendly.
 [browser_967000_button_sync.js]
-skip-if = e10s # Bug ?????? - test uses promiseTabLoadEvent() which isn't e10s friendly.
 [browser_967000_button_tabView.js]
 [browser_968447_bookmarks_toolbar_items_in_panel.js]
 skip-if = os == "linux" # Intemittent failures - bug 979207
@@ -129,6 +127,7 @@ skip-if = os == "linux"
 skip-if = os == "linux"
 
 [browser_985815_propagate_setToolbarVisibility.js]
+skip-if = e10s # bug 1090635
 [browser_981305_separator_insertion.js]
 [browser_988072_sidebar_events.js]
 [browser_989338_saved_placements_not_resaved.js]
@@ -138,6 +137,7 @@ skip-if = os == "linux"
 [browser_987185_syncButton.js]
 [browser_987492_window_api.js]
 [browser_987640_charEncoding.js]
+skip-if = e10s # Bug 1088710
 [browser_992747_toggle_noncustomizable_toolbar.js]
 [browser_993322_widget_notoolbar.js]
 [browser_995164_registerArea_during_customize_mode.js]
diff --git a/browser/components/loop/content/shared/js/mixins.js b/browser/components/loop/content/shared/js/mixins.js
index 0480387c64c..008b5547fd6 100644
--- a/browser/components/loop/content/shared/js/mixins.js
+++ b/browser/components/loop/content/shared/js/mixins.js
@@ -26,6 +26,37 @@ loop.shared.mixins = (function() {
     rootObject = obj;
   }
 
+  /**
+   * window.location mixin. Handles changes in the call url.
+   * Forces a reload of the page to ensure proper state of the webapp
+   *
+   * @type {Object}
+   */
+  var UrlHashChangeMixin = {
+    propTypes: {
+      onUrlHashChange: React.PropTypes.func.isRequired
+    },
+
+    componentDidMount: function() {
+      rootObject.addEventListener("hashchange", this.onUrlHashChange, false);
+    },
+
+    componentWillUnmount: function() {
+      rootObject.removeEventListener("hashchange", this.onUrlHashChange, false);
+    }
+  };
+
+  /**
+   * Document location mixin.
+   *
+   * @type {Object}
+   */
+  var DocumentLocationMixin = {
+    locationReload: function() {
+      rootObject.location.reload();
+    }
+  };
+
   /**
    * Dropdown menu mixin.
    * @type {Object}
@@ -151,6 +182,8 @@ loop.shared.mixins = (function() {
     AudioMixin: AudioMixin,
     setRootObject: setRootObject,
     DropdownMenuMixin: DropdownMenuMixin,
-    DocumentVisibilityMixin: DocumentVisibilityMixin
+    DocumentVisibilityMixin: DocumentVisibilityMixin,
+    DocumentLocationMixin: DocumentLocationMixin,
+    UrlHashChangeMixin: UrlHashChangeMixin
   };
 })();
diff --git a/browser/components/loop/standalone/content/js/webapp.js b/browser/components/loop/standalone/content/js/webapp.js
index 1751ed9fd94..fc5a40aac3b 100644
--- a/browser/components/loop/standalone/content/js/webapp.js
+++ b/browser/components/loop/standalone/content/js/webapp.js
@@ -859,6 +859,10 @@ loop.webapp = (function($, _, OT, mozL10n) {
    * of the webapp page.
    */
   var WebappRootView = React.createClass({displayName: 'WebappRootView',
+
+    mixins: [sharedMixins.UrlHashChangeMixin,
+             sharedMixins.DocumentLocationMixin],
+
     propTypes: {
       client: React.PropTypes.instanceOf(loop.StandaloneClient).isRequired,
       conversation: React.PropTypes.oneOfType([
@@ -879,6 +883,10 @@ loop.webapp = (function($, _, OT, mozL10n) {
       };
     },
 
+    onUrlHashChange: function() {
+      this.locationReload();
+    },
+
     render: function() {
       if (this.state.unsupportedDevice) {
         return UnsupportedDeviceView(null);
diff --git a/browser/components/loop/standalone/content/js/webapp.jsx b/browser/components/loop/standalone/content/js/webapp.jsx
index 1c4b302d313..6184f3ba82a 100644
--- a/browser/components/loop/standalone/content/js/webapp.jsx
+++ b/browser/components/loop/standalone/content/js/webapp.jsx
@@ -859,6 +859,10 @@ loop.webapp = (function($, _, OT, mozL10n) {
    * of the webapp page.
    */
   var WebappRootView = React.createClass({
+
+    mixins: [sharedMixins.UrlHashChangeMixin,
+             sharedMixins.DocumentLocationMixin],
+
     propTypes: {
       client: React.PropTypes.instanceOf(loop.StandaloneClient).isRequired,
       conversation: React.PropTypes.oneOfType([
@@ -879,6 +883,10 @@ loop.webapp = (function($, _, OT, mozL10n) {
       };
     },
 
+    onUrlHashChange: function() {
+      this.locationReload();
+    },
+
     render: function() {
       if (this.state.unsupportedDevice) {
         return <UnsupportedDeviceView />;
diff --git a/browser/components/loop/test/shared/mixins_test.js b/browser/components/loop/test/shared/mixins_test.js
index 3e98eef53bb..dc2872571b8 100644
--- a/browser/components/loop/test/shared/mixins_test.js
+++ b/browser/components/loop/test/shared/mixins_test.js
@@ -21,6 +21,75 @@ describe("loop.shared.mixins", function() {
     sandbox.restore();
   });
 
+  describe("loop.webapp.UrlHashChangeMixin", function() {
+    function createTestComponent(onUrlHashChange) {
+      var TestComp = React.createClass({
+        mixins: [loop.shared.mixins.UrlHashChangeMixin],
+        onUrlHashChange: onUrlHashChange || function(){},
+        render: function() {
+          return React.DOM.div();
+        }
+      });
+      return new TestComp();
+    }
+
+    it("should watch for hashchange event", function() {
+      var addEventListener = sandbox.spy();
+      sharedMixins.setRootObject({
+        addEventListener: addEventListener
+      });
+
+      TestUtils.renderIntoDocument(createTestComponent());
+
+      sinon.assert.calledOnce(addEventListener);
+      sinon.assert.calledWith(addEventListener, "hashchange");
+    });
+
+    it("should call onUrlHashChange when the url is updated", function() {
+      sharedMixins.setRootObject({
+        addEventListener: function(name, cb) {
+          if (name === "hashchange") {
+            cb();
+          }
+        }
+      });
+      var onUrlHashChange = sandbox.stub();
+
+      TestUtils.renderIntoDocument(createTestComponent(onUrlHashChange));
+
+      sinon.assert.calledOnce(onUrlHashChange);
+    });
+  });
+
+  describe("loop.webapp.DocumentLocationMixin", function() {
+    var reloadStub, TestComp;
+
+    beforeEach(function() {
+      reloadStub = sandbox.stub();
+
+      sharedMixins.setRootObject({
+        location: {
+          reload: reloadStub
+        }
+      });
+
+      TestComp = React.createClass({
+        mixins: [loop.shared.mixins.DocumentLocationMixin],
+        render: function() {
+          return React.DOM.div();
+        }
+      });
+    });
+
+    it("should call window.location.reload", function() {
+      var comp = TestUtils.renderIntoDocument(TestComp());
+
+      comp.locationReload();
+
+      sinon.assert.calledOnce(reloadStub);
+    });
+  });
+
   describe("loop.panel.DocumentVisibilityMixin", function() {
     var comp, TestComp, onDocumentVisibleStub, onDocumentHiddenStub;
 
diff --git a/browser/components/loop/test/standalone/webapp_test.js b/browser/components/loop/test/standalone/webapp_test.js
index 60b0f9a3eb6..2daf948bc49 100644
--- a/browser/components/loop/test/standalone/webapp_test.js
+++ b/browser/components/loop/test/standalone/webapp_test.js
@@ -514,7 +514,8 @@ describe("loop.webapp", function() {
         notifications: notifications,
         sdk: sdk,
         conversation: conversationModel,
-        feedbackApiClient: feedbackApiClient
+        feedbackApiClient: feedbackApiClient,
+        onUrlHashChange: sandbox.stub()
       }));
     }
 
diff --git a/browser/modules/UITour.jsm b/browser/modules/UITour.jsm
index 0680551d97e..7c457237f1f 100644
--- a/browser/modules/UITour.jsm
+++ b/browser/modules/UITour.jsm
@@ -838,7 +838,17 @@ this.UITour = {
       highlighter.parentElement.setAttribute("targetName", aTarget.targetName);
       highlighter.parentElement.hidden = false;
 
-      let targetRect = aTarget.node.getBoundingClientRect();
+      let highlightAnchor;
+      // If the target is in the overflow panel, just highlight the overflow button.
+      if (aTarget.node.getAttribute("overflowedItem")) {
+        let doc = aTarget.node.ownerDocument;
+        let placement = CustomizableUI.getPlacementOfWidget(aTarget.widgetName || aTarget.node.id);
+        let areaNode = doc.getElementById(placement.area);
+        highlightAnchor = areaNode.overflowable._chevron;
+      } else {
+        highlightAnchor = aTarget.node;
+      }
+      let targetRect = highlightAnchor.getBoundingClientRect();
       let highlightHeight = targetRect.height;
       let highlightWidth = targetRect.width;
       let minDimension = Math.min(highlightHeight, highlightWidth);
@@ -874,7 +884,7 @@ this.UITour = {
       let offsetY = paddingLeftPx
                       - (Math.max(0, highlightHeightWithMin - targetRect.height) / 2);
       this._addAnnotationPanelMutationObserver(highlighter.parentElement);
-      highlighter.parentElement.openPopup(aTarget.node, "overlap", offsetX, offsetY);
+      highlighter.parentElement.openPopup(highlightAnchor, "overlap", offsetX, offsetY);
     }
 
     // Prevent showing a panel at an undefined position.
diff --git a/browser/themes/linux/browser.css b/browser/themes/linux/browser.css
index 7cb769845f2..83ce7c1e11e 100644
--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -18,6 +18,23 @@
 %define conditionalForwardWithUrlbar window:not([chromehidden~="toolbar"]) #urlbar-wrapper
 %define conditionalForwardWithUrlbarWidth 30
 
+:root {
+  --toolbarbutton-hover-background: hsla(0,0%,100%,.3) linear-gradient(hsla(0,0%,100%,.7), hsla(0,0%,100%,.2));
+  --toolbarbutton-hover-boxshadow: 0 1px 0 hsla(0,0%,100%,.3) inset, 0 0 0 1px hsla(0,0%,100%,.2) inset, 0 1px 0 hsla(0,0%,0%,.03);
+  --toolbarbutton-hover-bordercolor: rgb(154,154,154);
+
+  --toolbarbutton-active-boxshadow: 0 1px 1px hsla(0,0%,0%,.1) inset, 0 0 1px hsla(0,0%,0%,.3) inset;
+  --toolbarbutton-active-bordercolor: rgb(154,154,154);
+  --toolbarbutton-active-background: rgba(154,154,154,.5) linear-gradient(hsla(0,0%,100%,.7), hsla(0,0%,100%,.4));
+
+  --toolbarbutton-checkedhover-backgroundcolor: rgba(90%,90%,90%,.4);
+
+  --toolbarbutton-combined-boxshadow: 0 0 0 1px hsla(0,0%,100%,.2);
+  --toolbarbutton-combined-backgroundimage: linear-gradient(hsla(210,54%,20%,.2) 0, hsla(210,54%,20%,.2) 18px);
+
+  --verified-identity-box-backgroundcolor: #fff;
+}
+
 #menubar-items {
   -moz-box-orient: vertical; /* for flex hack */
 }
@@ -590,12 +607,11 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1:not([disabled=true]):not([open]):hover > .toolbarbutton-menubutton-dropmarker > .dropmarker-icon,
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1:not([disabled=true]):hover > .toolbarbutton-badge-container > .toolbarbutton-icon,
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1:not([disabled=true]):hover > .toolbarbutton-icon {
-  background-color: hsla(0,0%,100%,.3);
-  background-image: linear-gradient(hsla(0,0%,100%,.7), hsla(0,0%,100%,.2));
-  border: 1px solid rgb(154,154,154);
-  box-shadow: 0 1px 0 hsla(0,0%,100%,.3) inset,
-              0 0 0 1px hsla(0,0%,100%,.2) inset,
-              0 1px 0 hsla(0,0%,0%,.03);
+  background: var(--toolbarbutton-hover-background);
+  border-width: 1px;
+  border-style: solid;
+  border-color: var(--toolbarbutton-hover-bordercolor);
+  box-shadow: var(--toolbarbutton-hover-boxshadow);
 }
 
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1:hover > .toolbarbutton-menubutton-dropmarker > .dropmarker-icon,
@@ -608,16 +624,16 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1[open="true"] > .toolbarbutton-menubutton-dropmarker:not([disabled=true]) > .dropmarker-icon,
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1:not([disabled=true]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-badge-container > .toolbarbutton-icon,
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1:not([disabled=true]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-icon {
-  background-color: rgba(154,154,154,.5);
-  background-image: linear-gradient(hsla(0,0%,100%,.7), hsla(0,0%,100%,.4));
-  border: 1px solid rgb(154,154,154);
-  box-shadow: 0 1px 1px hsla(0,0%,0%,.1) inset,
-              0 0 1px hsla(0,0%,0%,.3) inset;
+  background: var(--toolbarbutton-active-background);
+  box-shadow: var(--toolbarbutton-active-boxshadow);
+  border-width: 1px;
+  border-style: solid;
+  border-color: var(--toolbarbutton-active-bordercolor);
   transition-duration: 10ms;
 }
 
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1[checked]:not(:active):hover > .toolbarbutton-icon {
-  background-color: rgba(90%,90%,90%,.4);
+  background-color: var(--toolbarbutton-checkedhover-backgroundcolor);
   transition: background-color 150ms;
 }
 
@@ -633,12 +649,12 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
   width: 1px;
   height: 18px;
   -moz-margin-end: -1px;
-  background-image: linear-gradient(hsla(210,54%,20%,.2) 0, hsla(210,54%,20%,.2) 18px);
+  background-image: var(--toolbarbutton-combined-backgroundimage);
   background-clip: padding-box;
   background-position: center;
   background-repeat: no-repeat;
   background-size: 1px 18px;
-  box-shadow: 0 0 0 1px hsla(0,0%,100%,.2);
+  box-shadow: var(--toolbarbutton-combined-boxshadow);
 }
 
 :-moz-any(#TabsToolbar, #nav-bar) .toolbarbutton-1 > .toolbarbutton-menubutton-dropmarker {
@@ -971,7 +987,7 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
 }
 
 #identity-box.verifiedIdentity:not(:-moz-lwtheme) {
-  background-color: #fff;
+  background-color: var(--verified-identity-box-backgroundcolor);
 }
 
 #identity-box:-moz-focusring {
diff --git a/browser/themes/windows/browser.css b/browser/themes/windows/browser.css
index f394de0572e..b6ded4bfd5f 100644
--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -17,6 +17,28 @@
 %define conditionalForwardWithUrlbar window:not([chromehidden~="toolbar"]) #urlbar-wrapper
 %define conditionalForwardWithUrlbarWidth 30
 
+:root {
+  --toolbarbutton-hover-background: hsla(210,4%,10%,.08);
+  --toolbarbutton-hover-bordercolor: hsla(210,4%,10%,.1);
+  --toolbarbutton-hover-boxshadow: none;
+
+  --toolbarbutton-active-background: hsla(210,4%,10%,.12);
+  --toolbarbutton-active-bordercolor: hsla(210,4%,10%,.2) transparent transparent;
+  --toolbarbutton-active-boxshadow: 0 1px 0 0 hsla(210,4%,10%,.1) inset;
+
+  --toolbarbutton-checkedhover-backgroundcolor: hsla(210,4%,10%,.12);
+
+  --toolbarbutton-combined-boxshadow: none;
+  --toolbarbutton-combined-backgroundimage: linear-gradient(hsla(210,54%,20%,.2) 0, hsla(210,54%,20%,.2) 16px);
+
+  --verified-identity-box-backgroundcolor: #FFF;
+
+  --urlbar-dropmarker-url: url("chrome://browser/skin/urlbar-history-dropmarker.png");
+  --urlbar-dropmarker-region: rect(0px, 11px, 14px, 0px);
+  --urlbar-dropmarker-hover-region: rect(0px, 22px, 14px, 11px);
+  --urlbar-dropmarker-active-region: rect(0px, 33px, 14px, 22px);
+}
+
 #menubar-items {
   -moz-box-orient: vertical; /* for flex hack */
 }
@@ -663,6 +685,27 @@ toolbar[brighttext] .toolbarbutton-1 > .toolbarbutton-menubutton-dropmarker {
        (-moz-os-version: windows-win7) {
 %endif
   /* < Win8 */
+  :root {
+    --toolbarbutton-hover-background: linear-gradient(hsla(0,0%,100%,.6), hsla(0,0%,100%,.1));
+    --toolbarbutton-hover-bordercolor: hsla(210,54%,20%,.15) hsla(210,54%,20%,.2) hsla(210,54%,20%,.25);
+    --toolbarbutton-hover-boxshadow: 0 1px hsla(0,0%,100%,.3) inset,
+                                     0 1px hsla(210,54%,20%,.03),
+                                     0 0 2px hsla(210,54%,20%,.1);
+
+    --toolbarbutton-active-background: hsla(210,54%,20%,.15) linear-gradient(hsla(0,0%,100%,.6), hsla(0,0%,100%,.1));
+    --toolbarbutton-active-bordercolor: hsla(210,54%,20%,.3) hsla(210,54%,20%,.35) hsla(210,54%,20%,.4);
+    --toolbarbutton-active-boxshadow: 0 1px 1px hsla(210,54%,20%,.1) inset,
+                                      0 0 1px hsla(210,54%,20%,.2) inset,
+/* allows keyhole-forward-clip-path to be used for non-hover as well as hover: */
+                                      0 1px 0 hsla(210,54%,20%,0),
+                                      0 0 2px hsla(210,54%,20%,0);
+
+    --toolbarbutton-checkedhover-backgroundcolor: rgba(90%,90%,90%,.4);
+
+    --toolbarbutton-combined-backgroundimage: linear-gradient(hsla(210,54%,20%,.2) 0, hsla(210,54%,20%,.2) 18px);
+    --toolbarbutton-combined-boxshadow: 0 0 0 1px hsla(0,0%,100%,.2);
+  }
+
   #nav-bar .toolbarbutton-1 > .toolbarbutton-icon,
   #nav-bar .toolbarbutton-1 > .toolbarbutton-text,
   #nav-bar .toolbarbutton-1 > .toolbarbutton-badge-container,
@@ -732,7 +775,8 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
   width: 1px;
   height: 16px;
   -moz-margin-end: -1px;
-  background-image: linear-gradient(hsla(210,54%,20%,.2) 0, hsla(210,54%,20%,.2) 16px);
+  background-image: var(--toolbarbutton-combined-backgroundimage);
+  box-shadow: var(--toolbarbutton-combined-boxshadow);
   background-clip: padding-box;
   background-position: center;
   background-repeat: no-repeat;
@@ -751,8 +795,9 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
 #nav-bar .toolbarbutton-1:not([disabled=true]):not([checked]):not([open]):not(:active):hover > .toolbarbutton-badge-container,
 @conditionalForwardWithUrlbar@ > #forward-button:not([open]):not(:active):not([disabled]):hover > .toolbarbutton-icon,
 #nav-bar .toolbarbutton-1:not([buttonover]):not([open]):not(:active):hover > .toolbarbutton-menubutton-dropmarker:not([disabled]) > .dropmarker-icon {
-  background-color: hsla(210,4%,10%,.08);
-  border-color: hsla(210,4%,10%,.1);
+  background: var(--toolbarbutton-hover-background);
+  border-color: var(--toolbarbutton-hover-bordercolor);
+  box-shadow: var(--toolbarbutton-hover-boxshadow);
 }
 
 %ifdef WINDOWS_AERO
@@ -762,17 +807,8 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
   /* < Win8 */
   #nav-bar .toolbarbutton-1:not(:hover):not(:active):not([open]) > .toolbarbutton-menubutton-dropmarker::before,
   #nav-bar .toolbaritem-combined-buttons > .toolbarbutton-1:-moz-any(:not(:hover):not([open]),[disabled]) + .toolbarbutton-1:-moz-any(:not(:hover):not([open]),[disabled])::before {
-    content: "";
-    display: -moz-box;
-    width: 1px;
     height: 18px;
-    -moz-margin-end: -1px;
-    background-image: linear-gradient(hsla(210,54%,20%,.2) 0, hsla(210,54%,20%,.2) 18px);
-    background-clip: padding-box;
-    background-position: center;
-    background-repeat: no-repeat;
     background-size: 1px 18px;
-    box-shadow: 0 0 0 1px hsla(0,0%,100%,.2);
   }
 
   #nav-bar .toolbarbutton-1 > .toolbarbutton-menubutton-button > .toolbarbutton-icon:-moz-locale-dir(ltr),
@@ -787,21 +823,6 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
     border-bottom-left-radius: 0;
   }
 
-  #nav-bar .toolbarbutton-1:not([disabled=true]) > .toolbarbutton-menubutton-button[open] + .toolbarbutton-menubutton-dropmarker > .dropmarker-icon,
-  #nav-bar .toolbarbutton-1:not([disabled]):-moz-any(:hover,[open]) > .toolbarbutton-menubutton-button > .toolbarbutton-icon,
-  #nav-bar .toolbarbutton-1:not([disabled]):hover > .toolbarbutton-menubutton-dropmarker > .dropmarker-icon,
-  #nav-bar .toolbarbutton-1:not([disabled]):not([checked]):not([open]):not(:active):hover > .toolbarbutton-icon,
-  #nav-bar .toolbarbutton-1:not([disabled]):not([checked]):not([open]):not(:active):hover > .toolbarbutton-text,
-  #nav-bar .toolbarbutton-1:not([disabled]):not([checked]):not([open]):not(:active):hover > .toolbarbutton-badge-container,
-  @conditionalForwardWithUrlbar@ > .toolbarbutton-1:-moz-any([disabled],:not([open]):not([disabled]):not(:active)) > .toolbarbutton-icon {
-    background-image: linear-gradient(hsla(0,0%,100%,.6), hsla(0,0%,100%,.1));
-    background-color: transparent;
-    border-color: hsla(210,54%,20%,.15) hsla(210,54%,20%,.2) hsla(210,54%,20%,.25);
-    box-shadow: 0 1px hsla(0,0%,100%,.3) inset,
-                0 1px hsla(210,54%,20%,.03),
-                0 0 2px hsla(210,54%,20%,.1);
-  }
-
   #nav-bar .toolbarbutton-1 > .toolbarbutton-menubutton-button:not([disabled]):not([open]):not(:active):hover > .toolbarbutton-icon,
   #nav-bar .toolbarbutton-1:not([buttonover]):not([open]):not(:active):hover > .toolbarbutton-menubutton-dropmarker:not([disabled]) > .dropmarker-icon,
   @conditionalForwardWithUrlbar@ > #forward-button:not([open]):not(:active):not([disabled]):hover > .toolbarbutton-icon {
@@ -819,9 +840,9 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
 #nav-bar .toolbarbutton-1:not([disabled=true]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-icon,
 #nav-bar .toolbarbutton-1:not([disabled=true]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-text,
 #nav-bar .toolbarbutton-1:not([disabled=true]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-badge-container {
-  background-color: hsla(210,4%,10%,.12);
-  border-top-color: hsla(210,4%,10%,.2);
-  box-shadow: 0 1px 0 0 hsla(210,4%,10%,.1) inset;
+  background: var(--toolbarbutton-active-background);
+  border-color: var(--toolbarbutton-active-bordercolor);
+  box-shadow: var(--toolbarbutton-active-boxshadow);
   transition-duration: 10ms;
 }
 
@@ -835,14 +856,6 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
   #nav-bar .toolbarbutton-1:not([disabled]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-icon,
   #nav-bar .toolbarbutton-1:not([disabled]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-text,
   #nav-bar .toolbarbutton-1:not([disabled]):-moz-any([open],[checked],:hover:active) > .toolbarbutton-badge-container {
-    background-image: linear-gradient(hsla(0,0%,100%,.6), hsla(0,0%,100%,.1));
-    background-color: hsla(210,54%,20%,.15);
-    border-color: hsla(210,54%,20%,.3) hsla(210,54%,20%,.35) hsla(210,54%,20%,.4);
-    box-shadow: 0 1px 1px hsla(210,54%,20%,.1) inset,
-                0 0 1px hsla(210,54%,20%,.2) inset,
-                /* allows keyhole-forward-clip-path to be used for non-hover as well as hover: */
-                0 1px 0 hsla(210,54%,20%,0),
-                0 0 2px hsla(210,54%,20%,0);
     text-shadow: none;
     transition: none;
   }
@@ -852,7 +865,7 @@ toolbarbutton[sdk-button="true"][cui-areatype="toolbar"] > .toolbarbutton-icon {
   }
 
   #nav-bar .toolbarbutton-1[checked]:not(:active):hover > .toolbarbutton-icon {
-    background-color: rgba(90%,90%,90%,.4);
+    background-color: var(--toolbarbutton-checkedhover-backgroundcolor);
     transition: background-color .4s;
   }
 %ifdef WINDOWS_AERO
@@ -1317,7 +1330,7 @@ html|*.urlbar-input:-moz-lwtheme::-moz-placeholder,
 }
 
 #identity-box.verifiedIdentity:not(:-moz-lwtheme) {
-  background-color: #fff;
+  background-color: var(--verified-identity-box-backgroundcolor);
 }
 
 #identity-box:-moz-focusring {
@@ -1338,19 +1351,19 @@ html|*.urlbar-input:-moz-lwtheme::-moz-placeholder,
   background-color: transparent;
   border: none;
   width: auto;
-  list-style-image: url("chrome://browser/skin/urlbar-history-dropmarker.png");
-  -moz-image-region: rect(0px, 11px, 14px, 0px);
+  list-style-image: var(--urlbar-dropmarker-url);
+  -moz-image-region: var(--urlbar-dropmarker-region);
 }
 
 .urlbar-history-dropmarker:hover {
   background-image: radial-gradient(circle closest-side, hsla(205,100%,70%,.3), transparent);
-  -moz-image-region: rect(0px, 22px, 14px, 11px);
+  -moz-image-region: var(--urlbar-dropmarker-hover-region);
 }
 
 .urlbar-history-dropmarker:hover:active,
 .urlbar-history-dropmarker[open="true"] {
   background-image: radial-gradient(circle closest-side, hsla(205,100%,70%,.1), transparent);
-  -moz-image-region: rect(0px, 33px, 14px, 22px);
+  -moz-image-region: var(--urlbar-dropmarker-active-region);
 }
 
 /* page proxy icon */
diff --git a/browser/themes/windows/customizableui/panelUIOverlay.css b/browser/themes/windows/customizableui/panelUIOverlay.css
index 1e5f376d8d0..1c5343fff29 100644
--- a/browser/themes/windows/customizableui/panelUIOverlay.css
+++ b/browser/themes/windows/customizableui/panelUIOverlay.css
@@ -30,8 +30,8 @@
 #BMB_bookmarksPopup menupopup[placespopup=true] > hbox {
   /* emulating chrome://browser/content/places/menu.xml#places-popup-arrow but without the arrow */
   box-shadow: 0 0 4px rgba(0,0,0,0.2);
-  background: #FFF;
-  border: 1px solid rgba(0,0,0,0.25);
+  background: var(--panel-arrowcontent-background);
+  border: var(--panel-arrowcontent-border);
   border-radius: 3.5px;
   margin-top: -4px;
 }
diff --git a/browser/themes/windows/searchbar.css b/browser/themes/windows/searchbar.css
index c7eca8cf5f1..eaddc708630 100644
--- a/browser/themes/windows/searchbar.css
+++ b/browser/themes/windows/searchbar.css
@@ -2,6 +2,10 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+.searchbar-dropmarker-image {
+  --searchbar-dropmarker-url: url("chrome://browser/skin/searchbar-dropdown-arrow.png");
+}
+
 .autocomplete-textbox-container {
   -moz-box-align: stretch;
 }
@@ -38,7 +42,7 @@
 }
 
 .searchbar-dropmarker-image {
-  list-style-image: url("chrome://browser/skin/searchbar-dropdown-arrow.png");
+  list-style-image: var(--searchbar-dropmarker-url);
   -moz-image-region: rect(0, 13px, 11px, 0);
 }
 
diff --git a/toolkit/themes/windows/global/popup.css b/toolkit/themes/windows/global/popup.css
index f3183e08e96..1993c9ea19c 100644
--- a/toolkit/themes/windows/global/popup.css
+++ b/toolkit/themes/windows/global/popup.css
@@ -4,6 +4,13 @@
 
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
+/* ::::: Variables ::::: */
+.panel-arrowcontent {
+  --panel-arrowcontent-background: -moz-field;
+  --panel-arrowcontent-color: -moz-FieldText;
+  --panel-arrowcontent-border: 1px solid ThreeDShadow;
+}
+
 /* ::::: menupopup ::::: */
 
 menupopup,
@@ -49,10 +56,10 @@ panel[type="arrow"][side="right"] {
 
 .panel-arrowcontent {
   padding: 10px;
-  color: -moz-FieldText;
-  background: -moz-field;
+  color: var(--panel-arrowcontent-color);
+  background: var(--panel-arrowcontent-background);
   background-clip: padding-box;
-  border: 1px solid ThreeDShadow;
+  border: var(--panel-arrowcontent-border);
   margin: 4px;
 }
 
@@ -105,7 +112,7 @@ panel[type="arrow"][side="right"] {
 %ifdef XP_WIN
 @media (-moz-windows-default-theme) {
   .panel-arrowcontent {
-    border-color: hsla(210,4%,10%,.2);
+    --panel-arrowcontent-border: 1px solid hsla(210,4%,10%,.2);
     box-shadow: 0 0 4px hsla(210,4%,10%,.2);
   }
 
diff --git a/toolkit/xre/nsSigHandlers.cpp b/toolkit/xre/nsSigHandlers.cpp
index bc4250c07bf..cb4b4e68082 100644
--- a/toolkit/xre/nsSigHandlers.cpp
+++ b/toolkit/xre/nsSigHandlers.cpp
@@ -26,6 +26,7 @@
 #include <sys/resource.h>
 #include <unistd.h>
 #include <stdlib.h> // atoi
+#include <sys/prctl.h>
 #ifndef ANDROID // no Android impl
 #  include <ucontext.h>
 #endif
@@ -44,6 +45,13 @@ static unsigned int _gdb_sleep_duration = 300;
 #define CRAWL_STACK_ON_SIGSEGV
 #endif
 
+#ifndef PR_SET_PTRACER
+#define PR_SET_PTRACER 0x59616d61
+#endif
+#ifndef PR_SET_PTRACER_ANY
+#define PR_SET_PTRACER_ANY ((unsigned long)-1)
+#endif
+
 #if defined(CRAWL_STACK_ON_SIGSEGV)
 
 #include <unistd.h>
@@ -87,6 +95,9 @@ ah_crap_handler(int signum)
          _progname,
          getpid());
 
+  // Allow us to be ptraced by gdb on Linux with Yama restrictions enabled.
+  prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY);
+
   sleep(_gdb_sleep_duration);
 
   printf("Done sleeping...\n");