idlwave-shell-arrows-do-history

idlwave-shell-arrows-do-history is a variable defined in `idlw-shell.el'.
Its value is

t

Documentation:
Non-nil means UP and DOWN arrows move through command history.
This variable can have 3 values:
nil Arrows just move the cursor
t Arrows force the cursor back to the current command line and
walk the history
'cmdline When the cursor is in the current command line, arrows walk the
history. Everywhere else in the buffer, arrows move the cursor.

You can customize this variable.