I'm creating a form using openoffice writer.

When i add a form field, the program adds a border by default. 
I don't want to print that border, so I disable it (double click → border → no 
border).

The drawback is that the field becomes invisible. Compiling a form with 
invisible fields is a pain.

Microsoft Word works in a different manner: the form fields are highlighted by a 
gray background, so finding the fields is easy.
That background is not printable.
Acrobat reader does the same for pdf forms: it adds a blue background.