From the test script, it can be seen in the 'c' and 'e' characters that
right,center,left are working.

Numeric is not aligned to the decimal point.


package require Tk

set fixedFont {"Courier New" -12}

frame .f -width 100 -height 20
pack .f -side left
text .t -font $fixedFont -width 60 -height 10
pack .t -expand 1 -fill both

.t delete 1.0 end
.t tag configure x -tabs [list 30 left 60 right 90 left 120 right 140 left]
.t tag configure z -tabs [list 30 numeric 60 numeric 90 numeric 120 numeric 140 left]
.t tag configure c -tabs [list 30 center 60 center 90 center 120 center 140 left]
.t tag configure y -tabs [list 30 60 90 120 140]
.t insert 1.0
.t insert 2.0
.t insert 3.0
.t insert 4.0
    .t tag add x 1.0 2.0
    .t tag add z 2.0 3.0
    .t tag add c 3.0 4.0
    .t tag add y 4.0 end