Add flag to not recycle flyout blocks when switching languages

Fixes #1570

core/flyout_base.js

@@ -264,6 +264,14 @@ Blockly.Flyout.prototype.dragAngleRange_ = 70;
  */
 Blockly.Flyout.prototype.scrollAnimationFraction = 0.3;
 
+/**
+ * Whether to recycle blocks when refreshing the flyout. Nothing can be
+ * recycled when the locale changes.
+ * @type {boolean}
+ * @private
+ */
+Blockly.Flyout.prototype.recyclingEnabled_ = true;
+
 /**
  * Creates the flyout's DOM.  Only needs to be called once. The flyout can
  * either exist as its own svg element or be a g element nested inside a
@@ -681,6 +689,14 @@ Blockly.Flyout.prototype.setScrollPos = function(pos) {
   this.scrollbar_.set(pos * this.workspace_.scale);
 };
 
+/**
+ * Set whether the flyout can recycle blocks. A value of true allows blocks to be recycled.
+ * @param {boolean} recycle True if recycling is possible.
+ */
+Blockly.Flyout.prototype.setRecyclingEnabled = function(recycle) {
+  this.recyclingEnabled_ = recycle;
+};
+
 /**
  * Delete blocks and background buttons from a previous showing of the flyout.
  * @private
@@ -690,7 +706,7 @@ Blockly.Flyout.prototype.clearOldBlocks_ = function() {
   var oldBlocks = this.workspace_.getTopBlocks(false);
   for (var i = 0, block; block = oldBlocks[i]; i++) {
     if (block.workspace == this.workspace_) {
-      if (block.isRecyclable()) {
+      if (this.recyclingEnabled_ && block.isRecyclable()) {
         this.recycleBlock_(block);
       } else {
         block.dispose(false, false);

tests/vertical_playground.html

@@ -306,9 +306,11 @@
       }
 
       function setLocale(locale) {
+        workspace.getFlyout().setRecyclingEnabled(false);
         var xml = Blockly.Xml.workspaceToDom(workspace);
         Blockly.ScratchMsgs.setLocale(locale);
         Blockly.Xml.clearWorkspaceAndLoadFromXml(xml, workspace);
+        workspace.getFlyout().setRecyclingEnabled(true);
       }
     </script>
 

tests/vertical_playground_compressed.html

@@ -349,9 +349,11 @@
       }
 
       function setLocale(locale) {
+        workspace.getFlyout().setRecyclingEnabled(false);
         var xml = Blockly.Xml.workspaceToDom(workspace);
         Blockly.ScratchMsgs.setLocale(locale);
         Blockly.Xml.clearWorkspaceAndLoadFromXml(xml, workspace);
+        workspace.getFlyout().setRecyclingEnabled(true);
       }
     </script>