#18958
The 'blue underline' has nothing to do with a link (or vice versa). Coloring links blue and underlining them has been some kind of convention in Web environments, but that has not even been standardized. Actually, if you have a useful browser, you can change default settings that your links will be displayed green and italicized.
Wyss, Max. PDFzone (2003). Design>Publishing>Software>Adobe Acrobat
#21901
The Form tool as we know has been abandoned. There is now a Field tool which is subdivided into tools for the individual field types.
Wyss, Max. PDFzone (2004). Articles>Information Design>Forms>Adobe Acrobat
#14861
How To Make PDFs Compliant With Section 508 
First, if you don't produce forms for federal government, it is wasted time, but there is information available. Adobe has the accessibility section on its Web site with useful documentation. There are other Web sites about accessibility in general on all the federal government sites, and finally, there are further links from there. Also, if you are providing forms for a federal government agency, you should get in touch with their 'Section 508 representative,' who will give you guidelines for that agency's way to implement it.
Wyss, Max. PDFzone (2000). Design>Accessibility>Adobe Acrobat>Section 508
