Very interesting ! I tried it, it works, but not like I want. My problem is that, unlike I said in my previous message, it is not on a (complete) row I want to apply my format, but on a specific element. So, if you take my exemple again:

colum1 colum2 colum3
type1 row1
type2 row2 X
type2 row3 X
type3 row4
type1 row5
type2 row6 X
type2 row7 X
...

What I want is, all the elements in colum2 that are of row type type2 must have following inputmask: @l 999-9999.

I'll see if I can accomplish that with the tips you gave me.

Thanks again !

Hans