diff --git a/resources/celerity/map.php b/resources/celerity/map.php
index 01d2ec7b0b..68af3f37ef 100644
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -199,7 +199,7 @@ return array(
     'rsrc/externals/javelin/lib/Resource.js' => '44959b73',
     'rsrc/externals/javelin/lib/Routable.js' => 'b3e7d692',
     'rsrc/externals/javelin/lib/Router.js' => '29274e2b',
-    'rsrc/externals/javelin/lib/Scrollbar.js' => 'ef2ec0c6',
+    'rsrc/externals/javelin/lib/Scrollbar.js' => '5b2f5a08',
     'rsrc/externals/javelin/lib/URI.js' => '6eff08aa',
     'rsrc/externals/javelin/lib/Vector.js' => '2caa8fb8',
     'rsrc/externals/javelin/lib/WebSocket.js' => '3f840822',
@@ -672,7 +672,7 @@ return array(
     'javelin-resource' => '44959b73',
     'javelin-routable' => 'b3e7d692',
     'javelin-router' => '29274e2b',
-    'javelin-scrollbar' => 'ef2ec0c6',
+    'javelin-scrollbar' => '5b2f5a08',
     'javelin-stratcom' => '6c53634d',
     'javelin-tokenizer' => '7644823e',
     'javelin-typeahead' => '70baed2f',
@@ -1186,6 +1186,12 @@ return array(
       'javelin-vector',
       'javelin-dom',
     ),
+    '5b2f5a08' => array(
+      'javelin-install',
+      'javelin-dom',
+      'javelin-stratcom',
+      'javelin-vector',
+    ),
     '5bc2cb21' => array(
       'javelin-behavior',
       'javelin-stratcom',
@@ -1863,12 +1869,6 @@ return array(
       'phabricator-phtize',
       'javelin-dom',
     ),
-    'ef2ec0c6' => array(
-      'javelin-install',
-      'javelin-dom',
-      'javelin-stratcom',
-      'javelin-vector',
-    ),
     'efe49472' => array(
       'javelin-install',
       'javelin-util',
diff --git a/webroot/rsrc/externals/javelin/lib/Scrollbar.js b/webroot/rsrc/externals/javelin/lib/Scrollbar.js
index 37d6c166fb..2242e048b6 100644
--- a/webroot/rsrc/externals/javelin/lib/Scrollbar.js
+++ b/webroot/rsrc/externals/javelin/lib/Scrollbar.js
@@ -308,22 +308,30 @@ JX.install('Scrollbar', {
      * Figure out the correct size and offset of the scrollbar handle.
      */
     _resizeBar: function() {
+      // We're hiding and showing the bar itself, not just the handle, because
+      // pages that contain other panels may have scrollbars underneath the
+      // bar. If we don't hide the bar, it ends up eating clicks targeting
+      // these panels.
+
+      // Because the bar may be hidden, we can't measure it. Measure the
+      // viewport instead.
+
       var cdim = JX.Vector.getDim(this._content);
       var spos = JX.Vector.getAggregateScrollForNode(this._viewport);
-      var bdim = JX.Vector.getDim(this._bar);
+      var vdim = JX.Vector.getDim(this._viewport);
 
-      var ratio = bdim.y / cdim.y;
+      var ratio = vdim.y / cdim.y;
 
       var offset = Math.round(ratio * spos.y) + 2;
-      var size = Math.floor(ratio * (bdim.y - 2)) - 2;
+      var size = Math.floor(ratio * (vdim.y - 2)) - 2;
 
       if (size < cdim.y) {
         this._handle.style.top = offset + 'px';
         this._handle.style.height = size + 'px';
 
-        JX.DOM.show(this._handle);
+        JX.DOM.show(this._bar);
       } else {
-        JX.DOM.hide(this._handle);
+        JX.DOM.hide(this._bar);
       }
     },