Mandatory sub goal addition validation before submission

Summary:

Mandatory sub goal addition validation before submission

Content (required):

We have a goal plan with default goal Self Development; upon publishing the goal plan this goal will be added to each employee and they can add rest of their goals for manager approval. We want to make sure that each employee adds a sub-goal or task for the Self Development goal before submitting goals for approval to manager. Is there any way we can achieve this? Currently we are just displaying message to add sub-goal in section where employee clicks on submit button.

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