Fix spam-clicking Run button causing unhighlight error

js/activity.js

@@ -1666,6 +1666,11 @@ class Activity {
         };
 
         this._doFastButton = env => {
+            // Prevent spam-clicking by checking if already running
+            if (this.logo._alreadyRunning) {
+                return;
+            }
+
             this._onResize();
             this.blocks.activeBlock = null;
             hideDOMLabel();

js/blocks.js

@@ -2970,7 +2970,7 @@ class Blocks {
                 thisBlock = this.highlightedBlock;
             }
 
-            if (thisBlock !== null) {
+            if (thisBlock !== null && this.blockList[thisBlock]) {
                 this.blockList[thisBlock].unhighlight();
             }
 

js/blocks/__tests__/GraphicsBlocks.test.js

@@ -42,7 +42,7 @@ global.ValueBlock = class {
     }
 };
 
-global.FlowBlock = class extends global.ValueBlock {};
+global.FlowBlock = class extends global.ValueBlock { };
 global.FlowClampBlock = class extends global.FlowBlock {
     makeMacro = jest.fn();
 };
@@ -80,7 +80,9 @@ describe("GraphicsBlocks", () => {
         };
 
         activity = {
-            blocks: {},
+            blocks: {
+                blockList: []
+            },
             errorMsg: jest.fn(),
             turtles: {
                 companionTurtle: jest.fn(() => 0),