I was ‘wrong’, sorry, forgot a word, made it NOT transparent....
The mask field has to be on top (bring forward) of the regular field, but before you do that, put it half over that field, it’s easy to arrange the tab order, and make it not enterable via field format.
In layout make new taborder, where you remove the Maskfield from the order.
Still in layout mode, move the Maskfield to the final place.
If you use the taborder, you will go to the regular field, to enter a value, whereafter the value in the Maskfield will be showed.
If you want a samplefile with all possibilities discussed here, to take them apart, just let me know.
HTH
JW