It was fast, and
not sure there was a notification about size, and
got hanging winwcp.
Not a big issue, if repeats, will give more
details, but it was bit strange that winscp
tries to open binary file.
Again not a big problem, but
just letting you know as user that
sometimes it happens.

With 1 GB file, you should have got "Try to open large file?" confirmation. Did you?

1gb .zip file, and
this just by habit[ totalcmd]/accident i
just pressed Enter.

How big was the zip file? Why are you opening a zip file in WinSCP editor?

Sure:
- basic .zip file
- local
- 'press enter'

It was a big file, and i think it was the reason.
Just tested with smaller .zip and i see it open in wsp editor.
So no issue now, but
it was a strange that CPU got busy, and nothing; bit unexpected.
If happens again will report with more details.

Can you please be more specific? What ZIP file? Local or remote? What did you do get WinSCP hang?

So i tested latest 5.19 version, and
i expected to have ability to extract
from simple zip archive, and got
hanging winscp.

Could you implement ability to work
with archives and without caching
to disk, but to ram before transfer.

Thanks.