When uploading multiple files at once, only one progress bar is shown

Question

When I select multiple files at once (Image1 and Image2) I see only one progressbar as follows :

My upload widget looks like this

 uploader = new Uploader();
 uploader.addOnFinishUploadHandler(uploadHandler);
 uploader.avoidRepeatFiles(true);
 uploader.setAutoSubmit(true);
 uploaderPanel.add(uploader);
 progressBar = new ModalUploadStatus();
 uploader.setStatusWidget(progressBar);

And in the serverside I'm not using any custom servlet. Any suggestions ?

I'm using GWTupload 1.0.1 with GWT 2.4.0

EDIT

It seems that the uploader is uploading the two files as a bundle. Here is the log I'm getting during the upload :

INFO: server response transferred  14/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  14/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:55 EDT 2015 Gwt client Uploader
INFO: server response transferred  26/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  26/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:55 EDT 2015 Gwt client Uploader
INFO: server response transferred  33/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  33/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:56 EDT 2015 Gwt client Uploader
INFO: server response transferred  44/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  44/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:56 EDT 2015 Gwt client Uploader
INFO: server response transferred  52/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  52/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:57 EDT 2015 Gwt client Uploader
INFO: server response transferred  63/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  63/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:57 EDT 2015 Gwt client Uploader
INFO: server response transferred  70/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  70/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:58 EDT 2015 Gwt client Uploader
INFO: server response transferred  81/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  81/1407 [Image1.jpg, Image2.jpg]
INFO: Mon Jun 01 10:39:58 EDT 2015 Gwt client Uploader
INFO: server response transferred  89/1407 [Image1.jpg, Image2.jpg]
INFO: server response transferred  89/1407 [Image1.jpg, Image2.jpg]
...