Thank you for your help
this is indeed possible.
You can check if the change value is larger than one character.
If so, the change value is pasted from the clipboard.
All you need is to add this Script (FormCalc) to the change event of your field.
if (Len($event.change) gt 1) then $event.change = "" endif
Did you get the solution for this?
I have a similar requirement, which has e-mail and confirm e-mail fields.
Yes - the above solution works