Very large file - arrow navigation does not work correctly (or at all)

[Som30ne]

Hi All
(First I’d say that I likes the Morse signal in the forum title)

I’m trying to work with very large file (~700 MB).
It opens and displays fine, but - navigation/selection beyond 2M lines
is not working with arrow keys.
(Tried viewing the file as XML view and as Normal Text)

It’s very jittery and not very usable.

Is there anything that can be done to overcome this ?
Thanks.