Fix BOX and Dropbox file picker window never displayed

Steps to reproduce :

• Install live-connect
• Configure box (see screenshot for configuration on https://app.box.com/developers/console/app/507341/configuration)
• Log in as a regular user
• Add a file with Box to a folder with manage everything permissions
• A window asking for authorization is shown, click "authorize"
  Result : the window is closed
  Expected : display Box file picker
  N.B. : clicking on "add file" always shows authorization screen and not file picker

> tested ok on BOX on Safari , but ko on dropbox ( both safari and chrome)