About horizontal scroll bar

[Angelo Graziosi]

I notice that when I start Emacs (rev. 117589, MSYS2/MinGW64 build), the 
buffer which is active (that on which I worked in the previous session) 
does not display the horizontal scroll bar (HSB).

Switching to another buffer, this DISPLAYS the HSB. Switching back to 
the first buffer, now it DISPLAYS the HSB..

Is this to be expected?

Thanks,
Angelo.