Hi,
When in LC Designer set the presence of the row (named 'Row1') to hidden in the Object > Field palette.
Then in the click event of the button:
Row1.presence = "visible";
If the button and row are separated, in different subforms, then you will need a fuller reference in the script.
Check out the help file for the other settings you can use for the .presence property.
Good luck,
Niall