Index: work/remote/web/client/scripts/draw.js
===================================================================
--- work/remote/web/client/scripts/draw.js	(revision 5643)
+++ work/remote/web/client/scripts/draw.js	(revision 5644)
@@ -17,6 +17,9 @@
 	this.unit = options.unit || "mm";
 
 	this.canvas.imageSmoothingEnabled = false;
+	this.canvas.setTransform(1, 0, 0, 1, 0, 0);
+	this.canvas.fillStyle = "white";
+	this.canvas.fillRect(0, 0, this.canvas.canvas.width, this.canvas.canvas.height);
 	//this.canvas.globalAlpha = 0.5;
 
 	this.GCs = new Array(GC_MAX_COUNT);