I have a scenario where I need to create an application page that is installed to the ECB menu of a specific list only. Is this possible? or is the only way to do it associating the elements file with a list type e.g. task list?
This script must be placed in a webpart next to the list webpart (in a Content Editor Web Part for ex.)
The idea is not mine, here is the original article. Hope this will help.
It must be attached to a list template (if you are using the server side features), that has a specific id. I recommend that you create a feature with a hidden list template and list instance and then attaches your ECB to that list template.