File Source and File Sink under GnuRadio Companion v3.11.0.0

[user 1]

Hello,

I'm a beginner and I try to build under GRC, Operating System Ubuntu, a 
very simple system:

   File Source   --->   Throttle    --->   File Sink

The data transfer runs very well in a previous release of GnuRadio, but 
with my new installation of GnuRadio  v3.11.0.0 the transfer doesn't 
work anymore.

I discover on the File Source symbol new parameters:
  - Add begin tag, with default content:  pmt.PMT_NIL
  - Offset: 0
  - Length: 0

What is missing in my configuration to get the data tranfer OK, like 
previously ?

Thank you