diff --git a/resources/celerity/map.php b/resources/celerity/map.php
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -8,7 +8,7 @@
 return array(
   'names' => array(
     'core.pkg.css' => '974635bb',
-    'core.pkg.js' => '47fd11f0',
+    'core.pkg.js' => 'f0e2c091',
     'darkconsole.pkg.js' => 'df001cab',
     'differential.pkg.css' => '36884139',
     'differential.pkg.js' => '73337d1d',
@@ -412,7 +412,7 @@
     'rsrc/js/application/policy/behavior-policy-rule-editor.js' => 'fe9a552f',
     'rsrc/js/application/ponder/behavior-votebox.js' => '4e9b766b',
     'rsrc/js/application/projects/behavior-boards-dropdown.js' => '0ec56e1d',
-    'rsrc/js/application/projects/behavior-project-boards.js' => 'a6c6a058',
+    'rsrc/js/application/projects/behavior-project-boards.js' => '0676345e',
     'rsrc/js/application/projects/behavior-project-create.js' => '065227cc',
     'rsrc/js/application/projects/behavior-reorder-columns.js' => 'e1d25dfb',
     'rsrc/js/application/releeph/releeph-preview-branch.js' => 'b2b4fbaf',
@@ -438,7 +438,7 @@
     'rsrc/js/application/uiexample/notification-example.js' => '7a9677fc',
     'rsrc/js/core/Busy.js' => '6453c869',
     'rsrc/js/core/DragAndDropFileUpload.js' => '8c49f386',
-    'rsrc/js/core/DraggableList.js' => '2a6a1041',
+    'rsrc/js/core/DraggableList.js' => 'a16ec1c6',
     'rsrc/js/core/FileUpload.js' => 'a4ae61bf',
     'rsrc/js/core/Hovercard.js' => '7e8468ae',
     'rsrc/js/core/KeyboardShortcut.js' => '1ae869f2',
@@ -636,7 +636,7 @@
     'javelin-behavior-policy-control' => 'f3fef818',
     'javelin-behavior-policy-rule-editor' => 'fe9a552f',
     'javelin-behavior-ponder-votebox' => '4e9b766b',
-    'javelin-behavior-project-boards' => 'a6c6a058',
+    'javelin-behavior-project-boards' => '0676345e',
     'javelin-behavior-project-create' => '065227cc',
     'javelin-behavior-refresh-csrf' => '7814b593',
     'javelin-behavior-releeph-preview-branch' => 'b2b4fbaf',
@@ -713,7 +713,7 @@
     'phabricator-crumbs-view-css' => 'a49339de',
     'phabricator-dashboard-css' => 'a2bfdcbf',
     'phabricator-drag-and-drop-file-upload' => '8c49f386',
-    'phabricator-draggable-list' => '2a6a1041',
+    'phabricator-draggable-list' => 'a16ec1c6',
     'phabricator-fatal-config-template-css' => '25d446d6',
     'phabricator-feed-css' => '7bfc6f12',
     'phabricator-file-upload' => 'a4ae61bf',
@@ -851,6 +851,15 @@
       'javelin-stratcom',
       'javelin-workflow',
     ),
+    '0676345e' => array(
+      'javelin-behavior',
+      'javelin-dom',
+      'javelin-util',
+      'javelin-vector',
+      'javelin-stratcom',
+      'javelin-workflow',
+      'phabricator-draggable-list',
+    ),
     '06e05112' => array(
       'javelin-behavior',
       'javelin-stratcom',
@@ -987,14 +996,6 @@
       'javelin-install',
       'javelin-util',
     ),
-    '2a6a1041' => array(
-      'javelin-install',
-      'javelin-dom',
-      'javelin-stratcom',
-      'javelin-util',
-      'javelin-vector',
-      'javelin-magical-init',
-    ),
     '2b228192' => array(
       'javelin-behavior',
       'javelin-dom',
@@ -1477,6 +1478,14 @@
       'javelin-dom',
       'javelin-reactor-dom',
     ),
+    'a16ec1c6' => array(
+      'javelin-install',
+      'javelin-dom',
+      'javelin-stratcom',
+      'javelin-util',
+      'javelin-vector',
+      'javelin-magical-init',
+    ),
     'a4ae61bf' => array(
       'javelin-install',
       'javelin-dom',
@@ -1485,14 +1494,6 @@
     'a5d7cf86' => array(
       'javelin-dom',
     ),
-    'a6c6a058' => array(
-      'javelin-behavior',
-      'javelin-dom',
-      'javelin-util',
-      'javelin-stratcom',
-      'javelin-workflow',
-      'phabricator-draggable-list',
-    ),
     'a80d0378' => array(
       'javelin-behavior',
       'javelin-stratcom',
diff --git a/src/view/layout/AphrontMultiColumnView.php b/src/view/layout/AphrontMultiColumnView.php
--- a/src/view/layout/AphrontMultiColumnView.php
+++ b/src/view/layout/AphrontMultiColumnView.php
@@ -139,11 +139,14 @@
         ->addPadding(PHUI::PADDING_MEDIUM_BOTTOM);
     }
 
-    return phutil_tag(
+    return javelin_tag(
       'div',
         array(
           'class' => 'aphront-multi-column-view',
           'id' => $this->getID(),
+          // TODO: It would be nice to convert this to an AphrontTagView and
+          // use addSigil() from Workboards instead of hard-coding this.
+          'sigil' => 'aphront-multi-column-view',
         ),
         $board);
   }
diff --git a/webroot/rsrc/js/application/projects/behavior-project-boards.js b/webroot/rsrc/js/application/projects/behavior-project-boards.js
--- a/webroot/rsrc/js/application/projects/behavior-project-boards.js
+++ b/webroot/rsrc/js/application/projects/behavior-project-boards.js
@@ -3,6 +3,7 @@
  * @requires javelin-behavior
  *           javelin-dom
  *           javelin-util
+ *           javelin-vector
  *           javelin-stratcom
  *           javelin-workflow
  *           phabricator-draggable-list
@@ -88,6 +89,41 @@
     return 0;
   }
 
+  function getcontainer() {
+    return JX.DOM.find(
+      JX.$(config.boardID),
+      'div',
+      'aphront-multi-column-view');
+  }
+
+  function onbegindrag(item) {
+    // If the longest column on the board is taller than the window, the board
+    // will scroll vertically. Dragging an item to the longest column may
+    // make it longer, by the total height of the board, plus the height of
+    // the drop target.
+
+    // If this happens, the scrollbar will jump around and the scroll position
+    // can be adjusted in a disorienting way. To reproduce this, drag a task
+    // to the bottom of the longest column on a scrolling board and wave the
+    // task in and out of the column. The scroll bar will jump around and
+    // it will be hard to lock onto a target.
+
+    // To fix this, set the minimum board height to the current board height
+    // plus the size of the drop target (which is the size of the item plus
+    // a bit of margin). This makes sure the scroll bar never needs to
+    // recalculate.
+
+    var item_size = JX.Vector.getDim(item);
+    var container = getcontainer();
+    var container_size = JX.Vector.getDim(container);
+
+    container.style.minHeight = (item_size.y + container_size.y + 12) + 'px';
+  }
+
+  function onenddrag() {
+    getcontainer().style.minHeight = '';
+  }
+
   function ondrop(list, item, after) {
     list.lock();
     JX.DOM.alterClass(item, 'drag-sending', true);
@@ -151,6 +187,9 @@
 
     list.listen('didDrop', JX.bind(null, ondrop, list));
 
+    list.listen('didBeginDrag', JX.bind(null, onbegindrag));
+    list.listen('didEndDrag', JX.bind(null, onenddrag));
+
     lists.push(list);
 
     onupdate(cols[ii]);
diff --git a/webroot/rsrc/js/core/DraggableList.js b/webroot/rsrc/js/core/DraggableList.js
--- a/webroot/rsrc/js/core/DraggableList.js
+++ b/webroot/rsrc/js/core/DraggableList.js
@@ -53,6 +53,7 @@
     _ghostNode : null,
     _group : null,
     _lastMousePosition: null,
+    _lastAdjust: null,
 
     getRootNode : function() {
       return this._root;
@@ -174,7 +175,6 @@
 
       for (var ii = 0; ii < this._group.length; ii++) {
         this._group[ii]._clearTarget();
-        this._group[ii]._generateTargets();
       }
 
       if (!this.invoke('didBeginDrag', this._dragging).getPrevented()) {
@@ -189,17 +189,48 @@
       }
     },
 
-    _generateTargets : function() {
-      var targets = [];
-      var items = this.findItems();
-      for (var ii = 0; ii < items.length; ii++) {
-        targets.push({
-          item: items[ii],
-          y: JX.$V(items[ii]).y + (JX.Vector.getDim(items[ii]).y / 2)
-        });
+    _getTargets : function() {
+      if (this._targets === null) {
+        var targets = [];
+        var items = this.findItems();
+        for (var ii = 0; ii < items.length; ii++) {
+          var item = items[ii];
+
+          var ipos = JX.$V(item);
+          if (item == this._dragging) {
+            // If the item we're measuring is also the item we're dragging,
+            // we need to measure its position as though it was still in the
+            // list, not its current position in the document (which is
+            // under the cursor). To do this, adjust the measured position by
+            // removing the offsets we added to put the item underneath the
+            // cursor.
+            if (this._lastAdjust) {
+              ipos.x -= this._lastAdjust.x;
+              ipos.y -= this._lastAdjust.y;
+            }
+          }
+
+          targets.push({
+            item: items[ii],
+            y: ipos.y + (JX.Vector.getDim(items[ii]).y / 2)
+          });
+        }
+        targets.sort(function(u, v) { return v.y - u.y; });
+        this._targets = targets;
+      }
+
+      return this._targets;
+    },
+
+    _dirtyTargetCache: function() {
+      if (this._hasGroup()) {
+        var group = this._group;
+        for (var ii = 0; ii < group.length; ii++) {
+          group[ii]._targets = null;
+        }
+      } else {
+        this._targets = null;
       }
-      targets.sort(function(u, v) { return v.y - u.y; });
-      this._targets = targets;
 
       return this;
     },
@@ -264,7 +295,7 @@
 
     _getCurrentTarget : function(p) {
       var ghost = this.getGhostNode();
-      var targets = this._targets;
+      var targets = this._getTargets();
       var dragging = this._dragging;
 
       var adjust_h = JX.Vector.getDim(ghost).y;
@@ -348,6 +379,12 @@
         return;
       }
 
+      if (e.getType() == 'scroll') {
+        // If this is a scroll event, the positions of drag targets may have
+        // changed.
+        this._dirtyTargetCache();
+      }
+
       var p = JX.$V(this._lastMousePosition.x, this._lastMousePosition.y);
 
       var group = this._group;
@@ -402,6 +439,7 @@
       }
 
       p.y -= origin.y;
+      this._lastAdjust = new JX.Vector(p.x, p.y);
       p.setPos(this._dragging);
 
       e.kill();
@@ -442,6 +480,8 @@
       for (var ii = 0; ii < group.length; ii++) {
         JX.DOM.alterClass(group[ii].getRootNode(), 'drag-target-list', false);
         group[ii]._clearTarget();
+        group[ii]._dirtyTargetCache();
+        group[ii]._lastAdjust = null;
       }
 
       if (!this.invoke('didEndDrag', dragging).getPrevented()) {