diff --git a/core/flyout_dragger.js b/core/flyout_dragger.js
index a261de57f..6572302c1 100644
--- a/core/flyout_dragger.js
+++ b/core/flyout_dragger.js
@@ -62,19 +62,24 @@ Blockly.FlyoutDragger = function(flyout) {
 goog.inherits(Blockly.FlyoutDragger, Blockly.WorkspaceDragger);
 
 /**
- * Move the appropriate scrollbar to drag the flyout.
- * Since flyouts only scroll in one direction at a time, this will discard one
- * of the calculated values.
- * x and y are in pixels.
- * @param {number} x The new x position to move the scrollbar to.
- * @param {number} y The new y position to move the scrollbar to.
- * @private
+ * Move the flyout based on the most recent mouse movements.
+ * @param {!Blockly.utils.Coordinate} currentDragDeltaXY How far the pointer has
+ *     moved from the position at the start of the drag, in pixel coordinates.
+ * @package
  */
-Blockly.FlyoutDragger.prototype.updateScroll_ = function(x, y) {
-  // Move the scrollbar and the flyout will scroll automatically.
+Blockly.FlyoutDragger.prototype.drag = function(currentDragDeltaXY) {
+  // startScrollXY_ is assigned by the superclass.
+  var newXY = Blockly.utils.Coordinate.sum(this.startScrollXY_, currentDragDeltaXY);
+
+  // We can't call workspace.scroll because the flyout's workspace doesn't own
+  // it's own scrollbars. This is because (as of 2.20190722.1) the
+  // workspace's scrollbar property must be a scrollbar pair, rather than a
+  // single scrollbar.
+  // Instead we'll just expect setting the scrollbar to update the scroll of
+  // the workspace as well.
   if (this.horizontalLayout_) {
-    this.scrollbar_.set(x);
+    this.scrollbar_.set(-newXY.x);
   } else {
-    this.scrollbar_.set(y);
+    this.scrollbar_.set(-newXY.y);
   }
 };