From 87385b07211ec1ec853ed28595659a9d6c812a8e Mon Sep 17 00:00:00 2001
From: Neil Fraser <fraser@google.com>
Date: Thu, 28 Mar 2019 14:48:01 -0700
Subject: [PATCH] Make drag detection more robust.
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Previously, one could drag (and hold) a quark outside the bounds of a mutator bubble, then scroll, and the old code wouldn’t query the mutator for gestures.
---
 core/workspace_svg.js | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/core/workspace_svg.js b/core/workspace_svg.js
index ee1be8f36..4ec9b0e44 100644
--- a/core/workspace_svg.js
+++ b/core/workspace_svg.js
@@ -1305,10 +1305,14 @@ Blockly.WorkspaceSvg.prototype.isMovable = function() {
  */
 Blockly.WorkspaceSvg.prototype.onMouseWheel_ = function(e) {
   // Don't scroll or zoom anything if drag is in progress.
-  if (this.currentGesture_) {
-    e.preventDefault();
-    e.stopPropagation();
-    return;
+  // If a drag is occurring, then it involves a selected block on a workspace.
+  if (Blockly.selected) {
+    var currentWorkspace = Blockly.selected.workspace;
+    if (currentWorkspace && currentWorkspace.currentGesture_) {
+      e.preventDefault();
+      e.stopPropagation();
+      return;
+    }
   }
   var canWheelZoom = this.options.zoomOptions && this.options.zoomOptions.wheel;
   var canWheelMove = this.options.moveOptions && this.options.moveOptions.wheel;