Task dependencies are visualized as arrow lines between tasks on the gantt bars in the schedule view. However, if a task has too many dependencies or if it has a dependency to a hidden sub-task, it might be difficult to see all the dependencies this way.
To see all the dependencies of a task at a glance, simply hover on the dependency icon next to the task title. A table with all the dependencies will appear. The arrows represent the direction of the dependencies: to or from a task.
Click on the icon to be directed to the task info page where you can also find a list of all dependencies. You can add dependencies here as well.