I was having problems understanding the behavior of my form until I came across the document at http://www.adobe.com/devnet/reader/articles/reader_compatibility/readercomp_digitalsignatu res.pdf .
My use case, which is a little convoluted, so could probably be streamlined, is that my application server presents a PDF to the user in a browser for them to review / sign.
In some cases, I was getting the message "The document could not be signed." with no other explanation (unlike many other threads which cite more detailed messages with a similar feel).
After reading the section of that doc titled "Script changes prevent signing", I understand why since my form was making script changes
So, now that I understand the situation, I have some options to work around it but presently none are great.
The issue in a nut shell:
1. The form is delivered to the browser, so the notion of save/close/re-open/sign doesn't make sense
2. A button is on the form, with form submit on MouseUp. This is the part that causes problems ... the application server is generating the (same) MouseUp action for ANY button and, at this point, I don't have a way to prevent that.
3. My "illegal" script change was a Page Open script that replaced the MouseUp action to what it "should" be.
4. The problem button is one that I want MouseUp to fire a launchURL instead of a submit.
The workarounds I've considered:
1. Replace the button with a link or non-button fields that has the correct actions. Workable but not a great UI metaphor.
2. Putting the "right" action on the MouseDown. Also workable, but since this doesn't actually prevent the MouseUp from firing, it creates confusing user experience if I there are problems that prevent form submission (and I am not clear if the launchURL in fact prevents the form submission or not).
I have a similar, but less import case for a true submit button. I want to also send email on form submission, but since I cannot the form submission on MouseUp, there is no way for me to only send mail when the form is submitted (i.e. all required fields filled in). So, I am presently always sending the mail in MouseDown.