Indent level

Hi Expert,

As we want to input any tasks/activities in planning under activity > detail >  "To do" list after WBS Indent level reaches level 4 (i.e. X.x.x.x.x in our case).
It means activities should be permitted to be entered only up to indent level 4 i.e. it should not be added any activity if it's WBS indent reaches up to X.x.x.x or should be alerted to the user. Is it possible in our tool?

I know it will affect many things, but it looks useful for all & If we can't restrict using any parameter available, it can be given only alert as per parameter defined for WBS indent level limit.

Please find attachment for better understanding.