Yes we added the new Silverlight Multifile upload feature which does not currently support the drag and drop functionality. So, if you have the Add-in installed but also have the latest version of Silverlight you will see the Silverlight upload expereince and not the ActiveX upload expereince.
In case of Silverlight upload expereince you will see a file upload dialog where you can select multilple files to upload and it will be an asynchronous operation.
Please let us know if you still see issues with upload.