Resolve Design Wizard automatically introducing and accepting negative gradients along runs

The current design wizard in InfoDrainage, even when all design criteria are set to standard, allows for negative gradients to be included within the model and can often be missed without careful inspection or auditing. This then relies on going through every flow path with a fine toothcomb and sifting through gradients which become particularly with larger pipes/gradients. Should implement warning symbols visually along pipe to raise awareness as opposed to relying on reviewing multiple flow paths of which there may be many.