could be consumed by deleting from the bottom, leaving none to be removed from
the top. In this case, don't call grid_view_delete_lines with ny of 0 as this
is incorrect and causes a bounds check to fatal error if built with -DDEBUG.
screen interactive programs to preserve the screen contents. When activated, it
saves a copy of the visible grid and disables scrolling into and resizing out
of the history; when deactivated the visible data is restored and the history
reenabled.
terminal to be switched between several different windows and programs
displayed on one terminal be detached from one terminal and moved to another.
ok deraadt pirofti