When dependencies are enabled in Smartsheet, what action cannot be performed?

When dependencies are enabled in Smartsheet, editing parent rows in specific duration columns is not allowed, as it can disrupt the established task relationships and timelines. Dependencies create a sequence of tasks based on their relationships and constraints, and adjusting the duration of a parent row could lead to inconsistencies or conflicts in the dependencies of its child tasks.

For instance, if a parent task's duration is modified, it can potentially alter the start and finish dates of its dependent child tasks, creating a ripple effect that may not reflect the intended schedule. Thus, Smartsheet restricts such changes to maintain the integrity of the project plan.

While the other options involve actions that can still be performed under the conditions of enabled dependencies, the editing of parent rows' durations directly affects the foundational structure of task relationships, which is why it is restricted.