Salut Benoit,
in you Predefined constants
I miss the Language based decimal constant
exp.
IF Instr("0123456789."),Right(TextBox1.Text,1)) = 0 THEN
but the dot isn't everywhere the decimal sign.
better would be
IF Instr("0123456789" & gb.decimal ),Right(TextBox1.Text,1)) = 0 THEN
Amicalement
Charlie