Merge pull request #837 from nathan/optim

Optimizations

1 files changed, 9 insertions, 8 deletions

diff --git a/lists.js b/lists.js
index bd856fe..769b8b3 100644
--- a/lists.js
+++ b/lists.js
@@ -363,7 +363,7 @@ List.prototype.equalTo = function (other) {
 
 // ListWatcherMorph inherits from BoxMorph:
 
-ListWatcherMorph.prototype = new BoxMorph();
+ListWatcherMorph.prototype = Object.create(BoxMorph.prototype);
 ListWatcherMorph.prototype.constructor = ListWatcherMorph;
 ListWatcherMorph.uber = BoxMorph.prototype;
 
@@ -388,6 +388,13 @@ ListWatcherMorph.prototype.init = function (list, parentCell) {
     this.lastCell = null;
     this.parentCell = parentCell || null; // for circularity detection
 
+    ListWatcherMorph.uber.init.call(
+        this,
+        SyntaxElementMorph.prototype.rounding,
+        1.000001, // shadow bug in Chrome,
+        new Color(120, 120, 120)
+    );
+
     // elements declarations
     this.label = new StringMorph(
         localize('length: ') + this.list.length(),
@@ -436,13 +443,6 @@ ListWatcherMorph.prototype.init = function (list, parentCell) {
     this.plusButton.drawNew();
     this.plusButton.fixLayout();
 
-    ListWatcherMorph.uber.init.call(
-        this,
-        SyntaxElementMorph.prototype.rounding,
-        1.000001, // shadow bug in Chrome,
-        new Color(120, 120, 120)
-    );
-
     this.color = new Color(220, 220, 220);
     this.isDraggable = true;
     this.setExtent(new Point(80, 70).multiplyBy(
@@ -634,6 +634,7 @@ ListWatcherMorph.prototype.setStartIndex = function (index) {
 };
 
 ListWatcherMorph.prototype.fixLayout = function () {
+    if (!this.label) return;
     Morph.prototype.trackChanges = false;
     if (this.frame) {
         this.arrangeCells();