diff --git a/core/misc/displace.js b/core/misc/displace.js
index 9ca72f5..f2638f5 100644
--- a/core/misc/displace.js
+++ b/core/misc/displace.js
@@ -10,72 +10,28 @@
     left: 0
   };
 
-  var displacingElements = [];
-
   /**
    * Informs listeners of the current offset dimensions.
+   *
+   * @param Boolean refresh
+   *   - When true or undefined, causes the current offsets values to be
+   *   recalculated.
    */
-  function displace() {
-    calculateOffsets();
-    $(document).trigger('drupalViewportOffsetChange', offsets);
-  }
-
-  /**
-   * Returns the current offset dimensions.
-   */
-  displace.getOffsets = function (refresh) {
-    if (refresh) {
+  function displace (refresh) {
+    if (refresh === undefined || refresh) {
       calculateOffsets();
+      $(document).trigger('drupalViewportOffsetChange', offsets);
     }
     return offsets;
-  };
-
-  /**
-   * Registers elements that should be used to determine viewport offset sizes.
-   */
-  displace.registerElements = function (elements) {
-    // Wrap the elements in an array if just one element is provided.
-    elements = (!'length' in elements) ? [elements] : elements;
-    // Loop through each element and add it to the list of displacing
-    // elements for the given edge.
-    for (var i = 0, n = elements.length; i < n; i++) {
-      // The elements will be stored as DOM nodes for consistency.
-      var element = ('get' in elements[i]) ? elements[i].get() : elements[i];
-      displacingElements.push(element);
-    }
-
-    // Remove duplicates.
-    displacingElements = $.unique(displacingElements);
-  };
-
-  /**
-   * Removes elements from the list of displacing elements for an edge.
-   */
-  displace.removeElements = function (elements) {
-    var remove = [];
-
-    // Wrap the elements in an array if just one element is provided.
-    elements = (!'length' in elements) ? [elements] : elements;
-    for (var i = 0, n = elements.length; i < n; i++) {
-      var el = ('get' in elements[i]) ? elements[i].get() : elements[i];
-      remove.push(el);
-    }
-
-    // Filter displacingElements by provided elements
-    displacingElements = $.grep(displacingElements, function(el) {
-      return $.inArray(el, remove) === -1;
-    });
-  };
-
-  /**
-   * Returns the object that lists the displacing elements by edge.
-   */
-  displace.getElements = function () {
-    return displacingElements;
-  };
+  }
 
   /**
    * Determines the viewport offsets.
+   *
+   * Any element with the attribute data-offset-{edge} e.g. data-offset-top will
+   * be consider in the viewport offset calculations. If the attribute has a
+   * numeric value, that value will be used. If no value is provided, one will
+   * be calculated using the element's dimensions and placement.
    */
   function calculateOffsets () {
     // Perform the calculations on a local varialbe
@@ -85,78 +41,84 @@
       bottom: 0,
       left: 0
     }
-    // Go through the displacing elements on each edge and calculate the
-    // offset.
-    for (var i = 0, n = displacingElements.length; i < n; i++) {
-      var $el = $(displacingElements[i]);
-      // If the element is not visble, do not use its dimensions.
-      if (!$el.is(':visible')) {
-        continue;
-      }
-      // Go through each edge and add up the displacements.
-      for (var edge in offset) {
-        if (offset.hasOwnProperty(edge)) {
-          var displacement = 0;
-          // If the offset data attribute contains a displacing value, use it.
-          displacement = $el.attr('data-offset-' + edge);
-          // If the element's offset data attribute does not exists
-          // then move to another edge
-          if (typeof displacement === 'undefined') {
+    // Go through each edge and find the largest displacement.
+    for (var edge in offset) {
+      if (offset.hasOwnProperty(edge)) {
+        var $displacingElements = $('[data-offset-' + edge + ']');
+        for (var i = 0, n = $displacingElements.length; i < n; i++) {
+          var $el = $displacingElements.eq(i);
+          // If the element is not visble, do consider its dimensions.
+          if (!$el.is(':visible')) {
             continue;
           }
-          // Try to parse displacement to number
-          displacement = parseInt(displacement, 10);
+          // If the offset data attribute contains a displacing value, use it.
+          var displacement = parseInt($el.attr('data-offset-' + edge), 10);
           // If the element's offset data attribute exits
           // but is not a valid number then get the displacement
-          // dimensions directly form the element
-          if (typeof displacement !== 'number' || isNaN(displacement) || displacement < 0) {
-            var size = 0;
-            var docSize = 0;
-            // Get the offset of the element itself.
-            var placement = $el.offset()[(edge === 'left' || edge === 'right') ? 'left' : 'top'];
-            // Subtract scroll distance from placement to get the distance
-            // to the edge of the viewport.
-            placement = placement - window['scroll' + ((edge === 'right' || edge === 'left') ? 'X' : 'Y')];
-            // Find the displacement value according to the edge.
-            switch (edge) {
-              // Left and top elements displace as a sum of their own offset value
-              // plus their size.
-              case 'top':
-                size = $el.outerHeight();
-                // Total displacment is the sum of the elements placement and size.
-                displacement = placement + size;
-                break;
-              case 'left':
-                size = $el.outerWidth();
-                // Total displacment is the sum of the elements placement and size.
-                displacement = placement + size;
-                break;
-              // Right and bottom elements displace according to their left and
-              // top offset. Their size isn't important.
-              case 'bottom':
-                docSize = document.documentElement.clientHeight;
-                displacement = docSize - placement;
-                break;
-              case 'right':
-                docSize = document.documentElement.clientWidth;
-                displacement = docSize - placement;
-                break;
-              default:
-                displacement = 0;
-            }
+          // dimensions directly from the element.
+          if (typeof displacement !== 'number' || isNaN(displacement)) {
+            displacement = getRawOffset($el, edge);
           }
           // If the displacement value is larger than the current value for this
-          // edge, use the value.
+          // edge, use the displacement value.
           offset[edge] = Math.max(offset[edge], displacement);
         }
       }
     }
-    console.log(offset);
     // Store the calculated offset
     offsets = offset;
   }
 
   /**
+   * Calculates displacement for element based on its dimensions and placement.
+   *
+   * @param jQuery $el
+   *   - The jQuery element whose dimensions and placement will be measured.
+   *
+   * @param string edge
+   *   - The name of the edge of the viewport that the element is associated
+   *   with.
+   */
+  function getRawOffset ($el, edge) {
+    var size = 0;
+    var docSize = 0;
+    var displacement = 0;
+    // Get the offset of the element itself.
+    var placement = $el.offset()[(edge === 'left' || edge === 'right') ? 'left' : 'top'];
+    // Subtract scroll distance from placement to get the distance
+    // to the edge of the viewport.
+    placement = placement - window['scroll' + ((edge === 'right' || edge === 'left') ? 'X' : 'Y')];
+    // Find the displacement value according to the edge.
+    switch (edge) {
+      // Left and top elements displace as a sum of their own offset value
+      // plus their size.
+      case 'top':
+        size = $el.outerHeight();
+        // Total displacment is the sum of the elements placement and size.
+        displacement = placement + size;
+        break;
+      case 'left':
+        size = $el.outerWidth();
+        // Total displacment is the sum of the elements placement and size.
+        displacement = placement + size;
+        break;
+      // Right and bottom elements displace according to their left and
+      // top offset. Their size isn't important.
+      case 'bottom':
+        docSize = document.documentElement.clientHeight;
+        displacement = docSize - placement;
+        break;
+      case 'right':
+        docSize = document.documentElement.clientWidth;
+        displacement = docSize - placement;
+        break;
+      default:
+        displacement = 0;
+    }
+    return displacement;
+  }
+
+  /**
    * Assign the displace function to a property of the Drupal global object.
    */
   Drupal.displace = displace;
diff --git a/core/modules/overlay/overlay-parent.js b/core/modules/overlay/overlay-parent.js
index 52de4b4..0c47f2c 100644
--- a/core/modules/overlay/overlay-parent.js
+++ b/core/modules/overlay/overlay-parent.js
@@ -34,10 +34,6 @@ Drupal.behaviors.overlayParent = {
       return;
     }
 
-    // The overlay's positioning can be affected by other elements on the page.
-    // Get the current viewpor offset values.
-    Drupal.overlay.viewportOffsets = Drupal.displace.getOffsets(true);
-
     $(document)
       // Instead of binding a click event handler to every link we bind one to
       // the document and only handle events that bubble up. This allows other
@@ -110,6 +106,11 @@ Drupal.overlay.open = function (url) {
  * Create the underlying markup and behaviors for the overlay.
  */
 Drupal.overlay.create = function () {
+  // The overlay's positioning can be affected by other elements on the page.
+  // Get the current viewpor offset values.
+  this.viewportOffsets = Drupal.displace();
+
+  // Build the overlay container.
   this.$container = $(Drupal.theme('overlayContainer'))
     .appendTo(document.body);
 
@@ -491,7 +492,7 @@ Drupal.overlay.eventhandlerAlterDisplacedElements = function (event) {
 
   // Consider any element that should be visible above the overlay (such as
   // a toolbar).
-  $(Drupal.displace.getElements().top).add(Drupal.displace.getElements().bottom).each(function () {
+  $('[data-offset-top]').add('[data-offset-bottom]').each(function () {
     var data = $(this).data();
     var maxWidth = documentWidth;
     // In IE, Shadow filter makes element to overlap the scrollbar with 1px.
diff --git a/core/modules/toolbar/js/toolbar.js b/core/modules/toolbar/js/toolbar.js
index e4e929d..ce9970c 100644
--- a/core/modules/toolbar/js/toolbar.js
+++ b/core/modules/toolbar/js/toolbar.js
@@ -84,10 +84,6 @@ Drupal.behaviors.toolbar = {
       // Call setHeight on screen resize. Wrap it in debounce to prevent
       // setHeight from being called too frequently.
       var setHeight = Drupal.debounce(Drupal.toolbar.setHeight, 200);
-      // Register elements with Drupal.displace that could affect the size and
-      // placement of other UI components.
-      Drupal.displace.registerElements($toolbar);
-      Drupal.displace.registerElements($trays);
       // Attach behavior to the window.
       $(window)
         .on('resize.toolbar', setHeight);
@@ -211,14 +207,12 @@ Drupal.toolbar.setHeight = function () {
  * can adjust to the placement of the tray.
  */
 Drupal.toolbar.setTrayWidth = function () {
-  var $tray = $toolbar.find('.tray.active');
-  var trayWidth = $tray.hasClass('vertical') ? $tray.width() : 0;
-  var offset = $tray.attr('data-offset-left');
-  if (offset !== trayWidth) {
-    $tray.attr('data-offset-left', trayWidth);
-    // Trigger a recalculation of viewport displacing elements.
-    Drupal.displace();
-  }
+  // Remove the left offset from the trays.
+  $toolbar.find('.tray').removeAttr('data-offset-left');
+  // If an active vertical tray exists, mark it as an offset element.
+  $toolbar.find('.tray.vertical.active').attr('data-offset-left', '');
+  // Trigger a recalculation of viewport displacing elements.
+  Drupal.displace();
 };
 
 /**