support dragging blocks out from variable watchers

HISTORY.md

@@ -3,7 +3,7 @@
 ## in development:
 
 * **New Features:**
-    * support dragging blocks out from result bubbles and speech balloons
+    * support dragging blocks out from result bubbles, speech balloons and variable watchers
 * **Notable Changes:**
 * **Notable Fixes:**
     * fixed layout for scrolling custom categories, thanks, Eckart, for the bug report!
@@ -13,6 +13,7 @@
 ### 2022-01-22
 * blocks: support dragging blocks out from result bubbles
 * objects: support dragging blocks out from speech balloons
+* objects: support dragging blocks out from variable watchers
 
 ### 2022-01-21
 * new dev version

src/objects.js

@@ -10052,7 +10052,7 @@ SpriteBubbleMorph.prototype.dataAsMorph = function (data) {
         contents.bounds.setHeight(img.height);
         contents.cachedImage = img;
 
-        // support blocks to be dragged out of result bubbles:
+        // support blocks to be dragged out of speech balloons:
         contents.isDraggable = true;
 
         contents.selectForEdit = function () {
@@ -11383,6 +11383,7 @@ CellMorph.prototype.createContents = function () {
     // re-build my contents
     var txt,
         img,
+        myself = this,
         fontSize = SyntaxElementMorph.prototype.fontSize,
         isSameList = this.contentsMorph instanceof ListWatcherMorph
             && (this.contentsMorph.list === this.contents),
@@ -11451,6 +11452,27 @@ CellMorph.prototype.createContents = function () {
             this.contentsMorph.bounds.setWidth(img.width);
             this.contentsMorph.bounds.setHeight(img.height);
             this.contentsMorph.cachedImage = img;
+
+            // support blocks to be dragged out of watchers:
+            this.contentsMorph.isDraggable = true;
+
+            this.contentsMorph.selectForEdit = function () {
+                var script = myself.contents.toBlock(),
+                    prepare = script.prepareToBeGrabbed,
+                    ide = this.parentThatIsA(IDE_Morph);
+
+                script.prepareToBeGrabbed = function (hand) {
+                    prepare.call(this, hand);
+                    hand.grabOrigin = {
+                        origin: ide.palette,
+                        position: ide.palette.center()
+                    };
+                    this.prepareToBeGrabbed = prepare;
+                };
+
+                script.setPosition(this.position());
+                return script;
+            };
         } else if (this.contents instanceof Costume) {
             img = this.contents.thumbnail(new Point(40, 40));
             this.contentsMorph = new Morph();