Only one CUSTOM FileUploader per time useable

[kartenkarsten]

It is not possible to use more than one FileInputType.CUSTOM (it's a modifiable singelton)
Reproduce:

AddButton a = new AddButton().withRandomId();
FileInputType fileInputType = FileInputType.CUSTOM.with( a );
MultiUploader mu1 = new gwtupload.client.MultiUploader( fileInputType);

AddButton b = new AddButton().withRandomId();
FileInputType fileInputType2 = FileInputType.CUSTOM.with( b );
MultiUploader mu2 = new gwtupload.client.MultiUploader( fileInputType2);

now you will find that in mu2.fileInputType.widget and mu1.fileInputType.widget is b located and a is not referenced anymore.

Result:
uploader will be reinstanceiate after file selection. Therefore the button will be removed and add ed into the new upload Formular. The Problem is: it's the same Button for all uploaders - all are removed! but it will be reassigned only to one uploader => missing Buttons.