There are currently a couple of problems with the "Print" link:
1. When I save an LLD rule and click on the "Print" link I get the following error: "Critical error. Field "hostid" is mandatory.". The same with item and trigger prototypes.
2. After I save a graph prototype, the "Print" link takes to me normal graphs.

To fix these problems and avoid similar problems in the future we should change the link to work with javascript instead of having to reload the whole page.