Picking error 1281 for readPixels with MacOSX Chromium 6.0.452.0 (51117

OS: MacOSX Chromium 6.0.452.0 (51117) when testing picking with http://scenejs.org/previews/scenejs-0.7.7.0/examples/basic-picking/...

Debug log:

LOG START << s0: Creating shader: 'theCanvas;;;dirsddirsddirsd;;ttf'

Picking at (464, 67)

s0: Binding pick buffer

s0: Mapping pick index to color/node: 0 => {r:0.00390625, g:0, b:1}
spheres

s0: Registering node as "picked" event listener: SID path = {spheres}

s0: Mapping pick index to color/node: 1 => {r:0.0078125, g:0, b:1}
spheres/blue-group

s0: Mapping pick index to color/node: 2 => {r:0.01171875, g:0, b:1}
spheres/blue-group/right-blue-sphere

s0: Creating shader: 'theCanvas;picking'

s0: Mapping pick index to color/node: 3 => {r:0.015625, g:0, b:1} left-
blue-sphere

s0: Mapping pick index to color/node: 4 => {r:0.01953125, g:0, b:1}
green-group

s0: Registering node as "picked" event listener: SID path = {green-
group}

s0: Mapping pick index to color/node: 5 => {r:0.0234375, g:0, b:1}
green-group/right-green-sphere

s0: Registering node as "picked" event listener: SID path = {green-
group/right-green-sphere}

s0: Mapping pick index to color/node: 6 => {r:0.02734375, g:0, b:1}
left-green-sphere

s0: Registering node as "picked" event listener: SID path = {left-
green-sphere}

s0: Mapping pick index to color/node: 7 => {r:0.03125, g:0, b:1} red-
group

s0: Mapping pick index to color/node: 8 => {r:0.03515625, g:0, b:1}
red-group/red-group-sphere

WebGL error calling readPixels on WebGL canvas context - see console
log for details

Reading pick buffer - picked pixel(464, 67) = {r:0, g:0, b:0}

Unbinding pick buffer

Finished rendering..

No nodes picked

LOG ENDS <<

uses :

function readPickBuffer() {

   var context = boundPickBuf.canvas.context;
   /// >>> THIS WILL BLOW UP with magic error 1281 for readPixels
   var pix = context.readPixels(pickX,

boundPickBuf.canvas.canvas.height - pickY, 1, 1, context.RGBA,
context.UNSIGNED_BYTE);

   if (!pix) {  //  http://asalga.wordpress.com/2010/07/14/compensating-for-webgl-readpixels-spec-changes/
       pix = new WebGLUnsignedByteArray(4);
       context.readPixels(pickX, boundPickBuf.canvas.height -

pickY, 1, 1, context.RGBA, context.UNSIGNED_BYTE, pix);

   }
   if (debugCfg.logTrace) {
       SceneJS._loggingModule.info("Reading pick buffer - picked

pixel(" + pickX + ", " + pickY + ") = {r:" + pix[0] + ", g:" + pix[1]
+ ", b:" + pix[2] + "}");

   }
   pickedNodeIndex = (pix[0] + pix[1] * 256) - 1;

}