Adjust highlight when modifying active scripts

When dragging blocks out of a running script, adding blocks into a
running script, or editing inputs of a running script, the  script's
highlight should now adjust accordingly

blocks.js

@@ -557,6 +557,10 @@ SyntaxElementMorph.prototype.reactToGrabOf = function (grabbedMorph) {
         topBlock.allComments().forEach(function (comment) {
             comment.align(topBlock);
         });
+        if (topBlock.getHighlight()) {
+            topBlock.removeHighlight();
+            topBlock.addHighlight();
+        }
     }
 };
 
@@ -1148,6 +1152,7 @@ SyntaxElementMorph.prototype.fixLayout = function () {
                 1 : Math.floor(fontHeight(this.fontSize) / 3),
         bottomCorrection,
         needsHighlight = false,
+        top = this.topBlock(),
         initialExtent = this.extent();
 
     if ((this instanceof MultiArgMorph) && (this.slotSpec !== '%c')) {
@@ -1366,6 +1371,12 @@ SyntaxElementMorph.prototype.fixLayout = function () {
         }
     }
 
+    // fix highlights, if any
+    if (top.getHighlight()) {
+        top.removeHighlight();
+        top.addHighlight();
+    }
+
     // restore highlight:
     if (needsHighlight) {
         this.addHighlight();
@@ -2481,6 +2492,14 @@ BlockMorph.prototype.snap = function () {
     top.allComments().forEach(function (comment) {
         comment.align(top);
     });
+    // fix highlights, if any
+    if (this.getHighlight() && (this !== top)) {
+        this.removeHighlight();
+    }
+    if (top.getHighlight()) {
+        top.removeHighlight();
+        top.addHighlight();
+    }
 };
 
 // CommandBlockMorph ///////////////////////////////////////////////////

history.txt

@@ -1528,4 +1528,5 @@ ______
 ------
 * GUI, Blocks, BYOB, Widgets: Scaling Blocks and Scripts (shift-click on settings menu)
 * Widets: numerical prompts
-* GUI: #signup URL switch
+* GUI: #signup URL switch
+* Blocks: adjusting highlights when modifying active scripts