Turning off sticky navigation if navbar is taller than window

Conflicts:
	sass/_theme_layout.sass
	sphinx_rtd_theme/layout.html

sass/_theme_layout.sass

@@ -286,6 +286,6 @@ footer
   .wy-nav-content-wrap
     margin-left: 0
 
-.stickynav
+nav.stickynav
   position: fixed
   top: 0

sphinx_rtd_theme/layout.html

@@ -53,6 +53,15 @@
     <script type="text/javascript" src="_static/js/theme.js"></script>
   {% endif %}
 
+  {# STICKY NAVIGATION #}
+  {% if theme_sticky_navigation %}
+    <script type="text/javascript">
+        jQuery(function () {
+            SphinxRtdTheme.StickyNav.enable();
+        });
+    </script>
+  {% endif %}
+
   {% for cssfile in css_files %}
     <link rel="stylesheet" href="{{ pathto(cssfile, 1) }}" type="text/css" />
   {% endfor %}
@@ -94,7 +103,7 @@
   <div class="wy-grid-for-nav">
 
     {# SIDE NAV, TOGGLES ON MOBILE #}
-    <nav data-toggle="wy-nav-shift" class="wy-nav-side{% if theme_sticky_navigation %} stickynav{% endif %}">
+    <nav data-toggle="wy-nav-shift" class="wy-nav-side">
       <div class="wy-side-nav-search">
         <a href="{{ pathto(master_doc) }}" class="icon icon-home"> {{ project }}</a>
         {% include "searchbox.html" %}

sphinx_rtd_theme/static/js/theme.js

@@ -14,3 +14,50 @@ $( document ).ready(function() {
   });
   $("table.docutils:not(.field-list").wrap("<div class='wy-table-responsive'></div>");
 });
+
+window.SphinxRtdTheme = (function (jquery) {
+
+    var stickyNav = (function () {
+
+        var navBar,
+            win,
+            stickyNavCssClass = 'stickynav',
+
+            applyStickNav = function () {
+
+                if (navBar.height() <= win.height()) {
+
+                    navBar.addClass(stickyNavCssClass);
+
+                } else {
+
+                    navBar.removeClass(stickyNavCssClass);
+                }
+            },
+
+            enable = function () {
+
+                applyStickNav();
+
+                win.on('resize', applyStickNav);
+            },
+
+            init = function () {
+
+                navBar = jquery('nav.wy-nav-side:first');
+                win    = jquery(window);
+            };
+
+        jquery(init);
+
+        return {
+
+            enable : enable
+        };
+    }());
+
+    return {
+
+        StickyNav : stickyNav
+    };
+}($));