Thanks for your answer.
We use XMetal as external editor for our production tool. You have to acquire a lock for the document you want modify. This lock must be renewed periodically.
What I would like to have is kind of a timer / interval that triggers the lock renewal.
It would be nice to have something like this. But in my case there is a workaround. I will let the production tool renew the lock.
But the solution let XMetaL take care of that would have been a cleaner solution.