The following patch will size the canvas div to the correct width.
Tested on ff 3.5.7, and ie8

<nowiki><pre>
--- src/timeline.c
+++ src/timeline.c
@@ -502,19 +502,19 @@
     @   while( canvasDiv.hasChildNodes() ){
     @     canvasDiv.removeChild(canvasDiv.firstChild);
     @   }
     @   var canvasY = absoluteY("canvas");
     @   var left = absoluteX(rowinfo[0].id) - absoluteX("canvas") + 15;
-    @   var width = left + nrail*20 + 20;
+    @   var width = nrail*20;
     @   for(var i in rowinfo){
     @     rowinfo[i].y = absoluteY(rowinfo[i].id) + 10 - canvasY;
     @     rowinfo[i].x = left + rowinfo[i].r*20;
     @   }
     @   var btm = rowinfo[rowinfo.length-1].y + 20;
     @   canvasDiv.innerHTML = '<canvas id="timeline-canvas" '+
     @      'style="position:absolute;left:'+(left-5)+'px;"' +
-    @      ' width="'+(width-left+26)+'" height="'+btm+'"></canvas>';
+    @      ' width="'+width+'" height="'+btm+'"></canvas>';
     @   realCanvas = document.getElementById('timeline-canvas');
     @   var context;
     @   if( realCanvas && realCanvas.getContext
     @        && (context = realCanvas.getContext('2d'))) {
     @     drawBox = function(color,x0,y0,x1,y1) {