File Source and File Sink under GnuRadio Companion v3.11.0.0

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