Pathbar Gtk 3.6 window on moving

[Mariano Gaudix <marianocordobario3 gmail com>]

hello

I m  creating  a  simple  pathbar .

https://www.youtube.com/watch?v=qStNhwkZg90


¿ How i can  achieve   that    a window   at    change   the size    >>
hide a button   quickly  ?

I need  ,  that the    button be  hide  immediately    when  the   window
changed  of size    and   the  window  is  moving  .