While operating in Manually Schedule mode, Microsoft Project will display indication of Warnings and Suggestions through red and green wavy lines respectively as shown in the following illustration:
A warning informs you that a subtask is scheduled later than its corresponding summary task. To optimize the schedule, the subtask finish date must not be later than the corresponding summary task finish date.
A suggestion informs you that a subtask is scheduled to start earlier than or later than its corresponding summary task.
It is possible for a subtask to have a warning and a suggestion as shown in the following illustration:
Applies to: Microsoft Project, all versions since 2010.
