I have a field where I set up the OnChange property to the following.
UpdateContext({varCurrency: Text(Value(TXT_Budget.Text), "[$-en-US]$#,##0.00")})
Then in the Default property I use varCurrency.
My problem is that when I click a copy button I can't populate the field with Parent.Default. At least I haven't figured out how. The easiest way is to ditch the code to 'paint' the value into a currency value but it nice to have.