How do Warning Alerts works?

Answer

WBS Gantt-Chart uses the Warning Alerts to determine if the Issue was started before, during the planned or after the planned Start and Due date. Below are the description regarding the Warning Alerts: 

Green alert shows that the task started 3 days prior to the Start date

Open

Yellow alert indicates that tasks due to be carried out have not been started yet

Open

Red alert means that tasks due to be completed have not yet been completed