MCreator issue tracker has been migrated to GitHub.
Existing tickets have been migrated to GitHub. Please open new tickets on the GitHub tracker instead. If you do not have a GitHub account, all feature requests and bug reports from forums are still considered and checked by the maintainers.
The thing you are talking about is called event system. In 1.7.9, it was replaced with procedure system. Check these pages for more info:
Tips and tricks for the new procedure system
Tutorial: Custom crafting machine block
Procedure system
MCreator 1.7.9 - Procedure system, many improvements