From c489ca1fc95e68eaeb74bda11632f59687a89312 Mon Sep 17 00:00:00 2001
From: Neil Fraser <fraser@google.com>
Date: Sat, 7 Jan 2017 23:56:09 -0800
Subject: [PATCH 1/2] Option for moving one block from stack.

See thread in support group before merging.
---
 core/block_svg.js | 13 ++++++++++---
 core/constants.js |  8 +++++++-
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/core/block_svg.js b/core/block_svg.js
index 4bc170d53..95120a284 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -950,9 +950,16 @@ Blockly.BlockSvg.prototype.onMouseMove_ = function(e) {
       Blockly.dragMode_ = Blockly.DRAG_FREE;
       Blockly.longStop_();
       this.workspace.setResizesEnabled(false);
-      if (this.parentBlock_) {
-        // Push this block to the very top of the stack.
-        this.unplug();
+
+      var disconnectEffect = !!this.parentBlock_;
+      // If in a stack, either split the stack, or pull out single block.
+      var healStack = !Blockly.DRAG_STACK;
+      if (e.metaKey) {
+        healStack = !healStack;
+      }
+      // Push this block to the very top of the stack.
+      this.unplug(healStack);
+      if (disconnectEffect) {
         var group = this.getSvgRoot();
         group.translate_ = 'translate(' + newXY.x + ',' + newXY.y + ')';
         this.disconnectUiEffect();
diff --git a/core/constants.js b/core/constants.js
index 0f327e2d9..5ee26e201 100644
--- a/core/constants.js
+++ b/core/constants.js
@@ -54,10 +54,16 @@ Blockly.LONGPRESS = 750;
 
 /**
  * Prevent a sound from playing if another sound preceded it within this many
- * miliseconds.
+ * milliseconds.
  */
 Blockly.SOUND_LIMIT = 100;
 
+/**
+ * When dragging a block out of a stack, split the stack in two (true), or drag
+ * out the block healing the stack (false).
+ */
+Blockly.DRAG_STACK = true;
+
 /**
  * The richness of block colours, regardless of the hue.
  * Must be in the range of 0 (inclusive) to 1 (exclusive).

From c68684dda64340565b2218cbe7573f4cb1e7c1d6 Mon Sep 17 00:00:00 2001
From: Neil Fraser <fraser@google.com>
Date: Mon, 9 Jan 2017 22:55:17 -0800
Subject: [PATCH 2/2] Expand stack-drag modifier key to include alt and ctrl.

---
 core/block_svg.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/block_svg.js b/core/block_svg.js
index 95120a284..3cc1a59ac 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -954,7 +954,7 @@ Blockly.BlockSvg.prototype.onMouseMove_ = function(e) {
       var disconnectEffect = !!this.parentBlock_;
       // If in a stack, either split the stack, or pull out single block.
       var healStack = !Blockly.DRAG_STACK;
-      if (e.metaKey) {
+      if (e.altKey || e.ctrlKey || e.metaKey) {
         healStack = !healStack;
       }
       // Push this block to the very top of the stack.