1 files changed, 7 insertions, 3 deletions
diff --git a/paint.js b/paint.js
index 65ae1f6..6e4ae8b 100644
--- a/paint.js
+++ b/paint.js
@@ -81,7 +81,7 @@ var PaintColorPickerMorph;
 
 // A complete paint editor
 
-PaintEditorMorph.prototype = new DialogBoxMorph();
+PaintEditorMorph.prototype = Object.create(DialogBoxMorph.prototype);
 PaintEditorMorph.prototype.constructor = PaintEditorMorph;
 PaintEditorMorph.uber = DialogBoxMorph.prototype;
 
@@ -92,6 +92,7 @@ function PaintEditorMorph() {
 }
 
 PaintEditorMorph.prototype.init = function () {
+    PaintEditorMorph.uber.init.call(this);
     // additional properties:
     this.paper = null; // paint canvas
     this.oncancel = null;
@@ -476,7 +477,7 @@ PaintEditorMorph.prototype.getUserColor = function () {
 
 // A large hsl color picker
 
-PaintColorPickerMorph.prototype = new Morph();
+PaintColorPickerMorph.prototype = Object.create(Morph.prototype);
 PaintColorPickerMorph.prototype.constructor = PaintColorPickerMorph;
 PaintColorPickerMorph.uber = Morph.prototype;
 
@@ -485,6 +486,7 @@ function PaintColorPickerMorph(extent, action) {
 }
 
 PaintColorPickerMorph.prototype.init = function (extent, action) {
+    PaintColorPickerMorph.uber.init.call(this);
     this.setExtent(extent || new Point(200, 100));
     this.action = action || nop;
     this.drawNew();
@@ -552,7 +554,7 @@ PaintColorPickerMorph.prototype.mouseMove =
     modify its image, based on a 'tool' property.
 */
 
-PaintCanvasMorph.prototype = new Morph();
+PaintCanvasMorph.prototype = Object.create(Morph.prototype);
 PaintCanvasMorph.prototype.constructor = PaintCanvasMorph;
 PaintCanvasMorph.uber = Morph.prototype;
 
@@ -561,6 +563,7 @@ function PaintCanvasMorph(shift) {
 }
 
 PaintCanvasMorph.prototype.init = function (shift) {
+    PaintCanvasMorph.uber.init.call(this);
     this.rotationCenter = new Point(240, 180);
     this.dragRect = null;
     this.previousDragPoint = null;
@@ -961,6 +964,7 @@ PaintCanvasMorph.prototype.buildContents = function () {
 };
 
 PaintCanvasMorph.prototype.drawNew = function () {
+    if (!this.background) return;
     var can = newCanvas(this.extent());
     this.merge(this.background, can);
     this.merge(this.paper, can);