Adobe Reader X simply passed my custom protocol link to the default browser, that’s why I was looking at that document.
Also, Adobe Reader XI pops up this warning when I click on my txt://test link (can I attach an image here?):
“Security Warning”
“This document is trying to connect to:
test
If you trust this site, choose Allow. If you do not trust this site, choose Block”
Below is a checkbox (checked by default):
“Remember this action for this site for all PDF documents”
and three buttons:
“Allow”, “Block” and “Cancel”.
Wouldn’t such solution (to block them all) be a bit radical? It’s like not allowing you to run any programs because some of them are malicious.