fixed turning turbo-mode off programmatically

thanks, @jadga-h, for finding and reporting this!

HISTORY.md

@@ -5,6 +5,7 @@
 ### 2020-07-09
 * new dev version
 * threads: fixed FOR EACH for hybrid lists, thanks, Brian!
+* threads: fixed script execution behavior when turning turbo mode off programmatically, thanks, Jadga, for reporting it. 
 
 
 ## 6.0.0:

snap.html

@@ -9,7 +9,7 @@
         <script src="src/widgets.js?version=2020-07-01"></script>
         <script src="src/blocks.js?version=2020-07-02"></script>
         <script src="src/threads.js?version=2020-07-09"></script>
-        <script src="src/objects.js?version=2020-07-01"></script>
+        <script src="src/objects.js?version=2020-07-09"></script>
         <script src="src/gui.js?version=2020-07-08"></script>
         <script src="src/paint.js?version=2020-05-17"></script>
         <script src="src/lists.js?version=2020-07-01"></script>

src/objects.js

@@ -84,7 +84,7 @@ BlockEditorMorph, BlockDialogMorph, PrototypeHatBlockMorph,  BooleanSlotMorph,
 localize, TableMorph, TableFrameMorph, normalizeCanvas, VectorPaintEditorMorph,
 HandleMorph, AlignmentMorph, Process, XML_Element, WorldMap, copyCanvas*/
 
-modules.objects = '2020-July-01';
+modules.objects = '2020-July-09';
 
 var SpriteMorph;
 var StageMorph;
@@ -7889,8 +7889,8 @@ StageMorph.prototype.step = function () {
         this.stepGenericConditions();
     }
     if (this.isFastTracked && this.threads.processes.length) {
-        while ((Date.now() - this.lastTime) < 15) { // approx. 67 fps
-            this.threads.step();
+        while (this.isFastTracked && (Date.now() - this.lastTime) < 15) {
+            this.threads.step(); // approx. 67 fps
         }
         this.changed();
     } else {