diff --git a/browser/components/preferences/in-content/privacy.js b/browser/components/preferences/in-content/privacy.js
index 60cbc525dfc71..6b192de72e283 100644
--- a/browser/components/preferences/in-content/privacy.js
+++ b/browser/components/preferences/in-content/privacy.js
@@ -651,22 +651,22 @@ var gPrivacyPane = {
    * Displays a dialog from which individual parts of private data may be
    * cleared.
    */
-  clearPrivateDataNow: function (aClearEverything)
-  {
+  clearPrivateDataNow: function (aClearEverything) {
     var ts = document.getElementById("privacy.sanitize.timeSpan");
     var timeSpanOrig = ts.value;
-    if (aClearEverything)
+
+    if (aClearEverything) {
       ts.value = 0;
+    }
 
-    const Cc = Components.classes, Ci = Components.interfaces;
-    var glue = Cc["@mozilla.org/browser/browserglue;1"]
-                 .getService(Ci.nsIBrowserGlue);
-    glue.sanitize(window);
+    gSubDialog.open("chrome://browser/content/sanitize.xul", "resizable=no", null, () => {
+      // reset the timeSpan pref
+      if (aClearEverything) {
+        ts.value = timeSpanOrig;
+      }
 
-    // reset the timeSpan pref
-    if (aClearEverything)
-      ts.value = timeSpanOrig;
-    Services.obs.notifyObservers(null, "clear-private-data", null);
+      Services.obs.notifyObservers(null, "clear-private-data", null);
+    });
   },
 
   /**
diff --git a/browser/components/preferences/in-content/subdialogs.js b/browser/components/preferences/in-content/subdialogs.js
index 90673367e54f3..71f0cd51ce85b 100644
--- a/browser/components/preferences/in-content/subdialogs.js
+++ b/browser/components/preferences/in-content/subdialogs.js
@@ -173,6 +173,18 @@ var gSubDialog = {
 
     this._frame.contentWindow.addEventListener("dialogclosing", this);
 
+    let oldResizeBy = this._frame.contentWindow.resizeBy;
+    this._frame.contentWindow.resizeBy = function(resizeByWidth, resizeByHeight) {
+      // Only handle resizeByHeight currently.
+      let frameHeight = gSubDialog._frame.clientHeight;
+      let boxMinHeight = parseFloat(getComputedStyle(gSubDialog._box).minHeight, 10);
+
+      gSubDialog._frame.style.height = (frameHeight + resizeByHeight) + "px";
+      gSubDialog._box.style.minHeight = (boxMinHeight + resizeByHeight) + "px";
+
+      oldResizeBy.call(gSubDialog._frame.contentWindow, resizeByWidth, resizeByHeight);
+    };
+
     // Make window.close calls work like dialog closing.
     let oldClose = this._frame.contentWindow.close;
     this._frame.contentWindow.close = function() {
@@ -273,8 +285,10 @@ var gSubDialog = {
     this._overlay.style.visibility = "visible";
     this._overlay.style.opacity = ""; // XXX: focus hack continued from _onContentLoaded
 
-    this._resizeObserver = new MutationObserver(this._onResize);
-    this._resizeObserver.observe(this._box, {attributes: true});
+    if (this._box.getAttribute("resizable") == "true") {
+      this._resizeObserver = new MutationObserver(this._onResize);
+      this._resizeObserver.observe(this._box, {attributes: true});
+    }
 
     this._trapFocus();
   },
diff --git a/browser/themes/linux/sanitizeDialog.css b/browser/themes/linux/sanitizeDialog.css
index 28d4e7eb30676..e73cd27e71312 100644
--- a/browser/themes/linux/sanitizeDialog.css
+++ b/browser/themes/linux/sanitizeDialog.css
@@ -56,7 +56,7 @@
   padding: 0;
   margin-top: 6px;
   margin-bottom: 6px;
-  margin-inline-start: -6px;
+  margin-inline-start: -4px;
   margin-inline-end: 0;
 }
 
diff --git a/browser/themes/shared/incontentprefs/preferences.inc.css b/browser/themes/shared/incontentprefs/preferences.inc.css
index 72ac39bc1e73b..577baa6ed507e 100644
--- a/browser/themes/shared/incontentprefs/preferences.inc.css
+++ b/browser/themes/shared/incontentprefs/preferences.inc.css
@@ -369,7 +369,6 @@ description > html|a {
 #dialogFrame {
   -moz-box-flex: 1;
   /* Default dialog dimensions */
-  height: 20em;
   width: 66ch;
 }
 
diff --git a/browser/tools/mozscreenshots/mozscreenshots/extension/configurations/Preferences.jsm b/browser/tools/mozscreenshots/mozscreenshots/extension/configurations/Preferences.jsm
index fc38a6abf34da..aa2b3f2a7cae0 100644
--- a/browser/tools/mozscreenshots/mozscreenshots/extension/configurations/Preferences.jsm
+++ b/browser/tools/mozscreenshots/mozscreenshots/extension/configurations/Preferences.jsm
@@ -23,6 +23,7 @@ this.Preferences = {
       ["paneApplications", null],
       ["panePrivacy", null],
       ["panePrivacy", null, DNTDialog],
+      ["panePrivacy", null, clearRecentHistoryDialog],
       ["paneSecurity", null],
       ["paneSync", null],
       ["paneAdvanced", "generalTab"],
@@ -107,6 +108,12 @@ function* connectionDialog(aBrowser) {
   });
 }
 
+function* clearRecentHistoryDialog(aBrowser) {
+  yield ContentTask.spawn(aBrowser, null, function* () {
+    content.document.getElementById("historyRememberClear").click();
+  });
+}
+
 function* certManager(aBrowser) {
   yield ContentTask.spawn(aBrowser, null, function* () {
     content.document.getElementById("viewCertificatesButton").click();
diff --git a/devtools/client/framework/toolbox-options.xhtml b/devtools/client/framework/toolbox-options.xhtml
index 8351c9c254ae7..372a588ab8455 100644
--- a/devtools/client/framework/toolbox-options.xhtml
+++ b/devtools/client/framework/toolbox-options.xhtml
@@ -84,6 +84,16 @@
         </label>
       </fieldset>
 
+      <fieldset id="debugger-options" class="options-groupbox">
+        <legend>&options.debugger.label;</legend>
+        <label title="&options.sourceMaps.tooltip;">
+          <input type="checkbox"
+                 id="debugger-sourcemaps"
+                 data-pref="devtools.debugger.client-source-maps-enabled"/>
+          <span>&options.sourceMaps.label;</span>
+        </label>
+      </fieldset>
+
       <fieldset id="styleeditor-options" class="options-groupbox">
         <legend>&options.styleeditor.label;</legend>
         <label title="&options.stylesheetSourceMaps.tooltip;">
diff --git a/devtools/client/framework/toolbox-process-window.js b/devtools/client/framework/toolbox-process-window.js
index 25e1492505f3f..8ead718b3da05 100644
--- a/devtools/client/framework/toolbox-process-window.js
+++ b/devtools/client/framework/toolbox-process-window.js
@@ -71,6 +71,7 @@ function setPrefDefaults() {
   // Bug 1225160 - Using source maps with browser debugging can lead to a crash
   Services.prefs.setBoolPref("devtools.debugger.source-maps-enabled", false);
   Services.prefs.setBoolPref("devtools.debugger.new-debugger-frontend", false);
+  Services.prefs.setBoolPref("devtools.debugger.client-source-maps-enabled", true);
 }
 
 window.addEventListener("load", function() {
diff --git a/devtools/client/locales/en-US/toolbox.dtd b/devtools/client/locales/en-US/toolbox.dtd
index 03f1080a806e9..6097fa82a7031 100644
--- a/devtools/client/locales/en-US/toolbox.dtd
+++ b/devtools/client/locales/en-US/toolbox.dtd
@@ -159,6 +159,15 @@
 <!ENTITY options.timestampMessages.label      "Enable timestamps">
 <!ENTITY options.timestampMessages.tooltip    "If you enable this option commands and output in the Web Console will display a timestamp">
 
+<!-- LOCALIZATION NOTE (options.debugger.label): This is the label for the
+  -  heading of the group of Debugger preferences in the options panel. -->
+<!ENTITY options.debugger.label            "Debugger">
+
+<!-- LOCALIZATION NOTE (options.sourceMap.label): This is the
+   - label for the checkbox that toggles source maps in the Debugger -->
+<!ENTITY options.sourceMaps.label      "Enable Source Maps">
+<!ENTITY options.sourceMaps.tooltip    "If you enable this option sources will be mapped in the Debugger and Console.">
+
 <!-- LOCALIZATION NOTE (options.styleeditor.label): This is the label for the
   -  heading of the group of Style Editor preferences in the options
   -  panel. -->
diff --git a/devtools/client/preferences/devtools.js b/devtools/client/preferences/devtools.js
index 1e47f18ac3f45..5f80b746a8466 100644
--- a/devtools/client/preferences/devtools.js
+++ b/devtools/client/preferences/devtools.js
@@ -95,6 +95,7 @@ pref("devtools.debugger.remote-timeout", 20000);
 pref("devtools.debugger.pause-on-exceptions", false);
 pref("devtools.debugger.ignore-caught-exceptions", true);
 pref("devtools.debugger.source-maps-enabled", true);
+pref("devtools.debugger.client-source-maps-enabled", true);
 pref("devtools.debugger.pretty-print-enabled", true);
 pref("devtools.debugger.auto-pretty-print", false);
 pref("devtools.debugger.auto-black-box", true);
diff --git a/devtools/server/actors/highlighters/box-model.js b/devtools/server/actors/highlighters/box-model.js
index 9902ef7c54ac3..aa37449282d00 100644
--- a/devtools/server/actors/highlighters/box-model.js
+++ b/devtools/server/actors/highlighters/box-model.js
@@ -4,10 +4,8 @@
 
 "use strict";
 
-const { Cu } = require("chrome");
 const { extend } = require("sdk/core/heritage");
 const { AutoRefreshHighlighter } = require("./auto-refresh");
-const { CssGridHighlighter } = require("./css-grid");
 const {
   CanvasFrameAnonymousContentHelper,
   createNode,
@@ -20,7 +18,6 @@ const {
 const { setIgnoreLayoutChanges } = require("devtools/shared/layout/utils");
 const inspector = require("devtools/server/actors/inspector");
 const nodeConstants = require("devtools/shared/dom-node-constants");
-const Services = require("Services");
 
 // Note that the order of items in this array is important because it is used
 // for drawing the BoxModelHighlighter's path elements correctly.
@@ -31,8 +28,6 @@ const GUIDE_STROKE_WIDTH = 1;
 // FIXME: add ":visited" and ":link" after bug 713106 is fixed
 const PSEUDO_CLASSES = [":hover", ":active", ":focus"];
 
-const GRID_ENABLED_PREF = "layout.css.grid.enabled";
-
 /**
  * The BoxModelHighlighter draws the box model regions on top of a node.
  * If the node is a block box, then each region will be displayed as 1 polygon.
@@ -97,10 +92,6 @@ const GRID_ENABLED_PREF = "layout.css.grid.enabled";
 function BoxModelHighlighter(highlighterEnv) {
   AutoRefreshHighlighter.call(this, highlighterEnv);
 
-  if (Services.prefs.getBoolPref(GRID_ENABLED_PREF)) {
-    this.cssGridHighlighter = new CssGridHighlighter(this.highlighterEnv);
-  }
-
   this.markup = new CanvasFrameAnonymousContentHelper(this.highlighterEnv,
     this._buildMarkup.bind(this));
 
@@ -263,11 +254,6 @@ BoxModelHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
   destroy: function () {
     AutoRefreshHighlighter.prototype.destroy.call(this);
     this.markup.destroy();
-
-    if (this.cssGridHighlighter) {
-      this.cssGridHighlighter.destroy();
-      this.cssGridHighlighter = null;
-    }
   },
 
   getElement: function (id) {
@@ -292,28 +278,6 @@ BoxModelHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
       this.options.region = "content";
     }
 
-    // Show the CSS grid highlighter if the current node is a grid container or grid item.
-    if (this.cssGridHighlighter) {
-      this.cssGridHighlighter.hide();
-      let gridNode;
-      if (this.currentNode &&
-          this.currentNode.getGridFragments &&
-          this.currentNode.getGridFragments().length) {
-        gridNode = this.currentNode;
-      } else if (this.currentNode.parentNode &&
-                 this.currentNode.parentNode.getGridFragments &&
-                 this.currentNode.parentNode.getGridFragments().length) {
-        gridNode = this.currentNode.parentNode;
-      }
-
-      if (gridNode) {
-        // Display the grid highlighter for the grid container and
-        // hide the box model guides.
-        this.cssGridHighlighter.show(gridNode);
-        this.options.hideGuides = true;
-      }
-    }
-
     let shown = this._update();
     this._trackMutations();
     this.emit("ready");
@@ -380,10 +344,6 @@ BoxModelHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
     this._hideBoxModel();
     this._hideInfobar();
 
-    if (this.cssGridHighlighter) {
-      this.cssGridHighlighter.hide();
-    }
-
     setIgnoreLayoutChanges(false, this.currentNode.ownerDocument.documentElement);
   },
 
diff --git a/devtools/server/actors/highlighters/css-grid.js b/devtools/server/actors/highlighters/css-grid.js
index ca6ede867d468..6c579620dba36 100644
--- a/devtools/server/actors/highlighters/css-grid.js
+++ b/devtools/server/actors/highlighters/css-grid.js
@@ -4,7 +4,6 @@
 
 "use strict";
 
-const { Cu } = require("chrome");
 const { extend } = require("sdk/core/heritage");
 const { AutoRefreshHighlighter } = require("./auto-refresh");
 const {
@@ -46,11 +45,7 @@ const GRID_GAP_PATTERN_STROKE_STYLE = "#9370DB";
 /**
  * Cached used by `CssGridHighlighter.getGridGapPattern`.
  */
-const gCachedGridPattern = new WeakMap();
-// WeakMap key for the Row grid pattern.
-const ROW_KEY = {};
-// WeakMap key for the Column grid pattern.
-const COLUMN_KEY = {};
+const gCachedGridPattern = new Map();
 
 /**
  * The CssGridHighlighter is the class that overlays a visual grid on top of
@@ -98,9 +93,6 @@ function CssGridHighlighter(highlighterEnv) {
 
   this.markup = new CanvasFrameAnonymousContentHelper(this.highlighterEnv,
     this._buildMarkup.bind(this));
-
-  this.onNavigate = this.onNavigate.bind(this);
-  this.highlighterEnv.on("navigate", this.onNavigate);
 }
 
 CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
@@ -211,9 +203,9 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
   },
 
   destroy() {
-    this.highlighterEnv.off("navigate", this.onNavigate);
-    this.markup.destroy();
     AutoRefreshHighlighter.prototype.destroy.call(this);
+    this.markup.destroy();
+    gCachedGridPattern.clear();
   },
 
   getElement(id) {
@@ -231,14 +223,13 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
   /**
    * Gets the grid gap pattern used to render the gap regions.
    *
-   * @param  {Object} dimension
-   *         Refers to the WeakMap key for the grid dimension type which is either the
-   *         constant COLUMN or ROW.
+   * @param  {String} dimensionType
+   *         The grid dimension type which is either the constant COLUMNS or ROWS.
    * @return {CanvasPattern} grid gap pattern.
    */
-  getGridGapPattern(dimension) {
-    if (gCachedGridPattern.has(dimension)) {
-      return gCachedGridPattern.get(dimension);
+  getGridGapPattern(dimensionType) {
+    if (gCachedGridPattern.has(dimensionType)) {
+      return gCachedGridPattern.get(dimensionType);
     }
 
     // Create the diagonal lines pattern for the rendering the grid gaps.
@@ -251,7 +242,7 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
     ctx.beginPath();
     ctx.translate(.5, .5);
 
-    if (dimension === COLUMN_KEY) {
+    if (dimensionType === COLUMNS) {
       ctx.moveTo(0, 0);
       ctx.lineTo(GRID_GAP_PATTERN_WIDTH, GRID_GAP_PATTERN_HEIGHT);
     } else {
@@ -263,19 +254,10 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
     ctx.stroke();
 
     let pattern = ctx.createPattern(canvas, "repeat");
-    gCachedGridPattern.set(dimension, pattern);
+    gCachedGridPattern.set(dimensionType, pattern);
     return pattern;
   },
 
-  /**
-   * Called when the page navigates. Used to clear the cached gap patterns and avoid
-   * using DeadWrapper objects as gap patterns the next time.
-   */
-  onNavigate() {
-    gCachedGridPattern.delete(ROW_KEY);
-    gCachedGridPattern.delete(COLUMN_KEY);
-  },
-
   _show() {
     if (Services.prefs.getBoolPref(CSS_GRID_ENABLED_PREF) && !this.isGrid()) {
       this.hide();
@@ -620,12 +602,11 @@ CssGridHighlighter.prototype = extend(AutoRefreshHighlighter.prototype, {
    */
   renderGridGap(linePos, startPos, endPos, breadth, dimensionType) {
     this.ctx.save();
+    this.ctx.fillStyle = this.getGridGapPattern(dimensionType);
 
     if (dimensionType === COLUMNS) {
-      this.ctx.fillStyle = this.getGridGapPattern(COLUMN_KEY);
       this.ctx.fillRect(linePos, startPos, breadth, endPos - startPos);
     } else {
-      this.ctx.fillStyle = this.getGridGapPattern(ROW_KEY);
       this.ctx.fillRect(startPos, linePos, endPos - startPos, breadth);
     }
 
@@ -729,10 +710,6 @@ exports.CssGridHighlighter = CssGridHighlighter;
  * @return {String} representation of the CSS grid fragment data.
  */
 function stringifyGridFragments(fragments = []) {
-  if (fragments[0] && Cu.isDeadWrapper(fragments[0])) {
-    return {};
-  }
-
   return JSON.stringify(fragments.map(getStringifiableFragment));
 }