= Tab display
TAB {on | off | clear | nn}
on :display tab char and DBCS(japanese) space.
Char used to display tab and its following space
is customaizable by .INI file parameter.
Default is Tab :Up-arrow
Tab-skip :Right arrow
DBCS space:shadow box
off :tab char is not displayed.
Special char for un-displayable char
is alaways displayed regardless this option.
clear :remove tab with space remained.
nn :Tab column interval,default is 4.
Tab key cause cursor jump not to next tab column
but jump to next field when tab column is 0.
Maximum 12.