What this color means?

Hello. I am trying the omniplan 3 an i create a gantt diagram for my startup project.
There is one task with one of its part with diferent color:

Can you tell me what this means?

Thank you for your time.

@conmac7 The bracket and grey shading circled in your Gantt chart indicates a start constraint - the date that the task can not be scheduled to start before. You can remove the start constraint by clicking the small x next to the field in the Task Inspector. Alternatively, you can hide constraints in the Gantt chart by selecting View > Gantt > Constraints in the OmniPlan menu bar.

Thank you very much for your answer