Improving auto scroll of nav to only scroll when necessary. Fully fixes #21

docs/js/custom.js

 
 // Automatically scroll the navigation menu to the active element
 //   https://github.com/civicrm/civicrm-dev-docs/issues/21
-$('.wy-nav-side')
-  .scrollTop(
-    $('li.toctree-l1.current').offset().top -
-    $('.wy-nav-side').offset().top -
-    80
-  );
+$.fn.isFullyWithinViewport = function(){
+    var viewport = {};
+    viewport.top = $(window).scrollTop();
+    viewport.bottom = viewport.top + $(window).height();
+    var bounds = {};
+    bounds.top = this.offset().top;
+    bounds.bottom = bounds.top + this.outerHeight();
+    return ( ! (
+      (bounds.top <= viewport.top) ||
+      (bounds.bottom >= viewport.bottom)
+    ) );
+};
+if( !$('li.toctree-l1.current').isFullyWithinViewport() ) {
+  $('.wy-nav-side')
+    .scrollTop(
+      $('li.toctree-l1.current').offset().top -
+      $('.wy-nav-side').offset().top -
+      60
+    );
+}