Second position is the position taken on by a model building block (stock, flow, converter, connector) whenever a decision process diamond or sub-model space is open. The clear second position menu item removes all second position information from all building blocks that are not in sub-models or decision process diamonds. Clear second position thus is a useful command to employ whenever you find that opening decision process diamonds or sub-models causes your diagram to become very messy. By removing all second position information, Clear Second Position gives you a mechanism for regaining control of the display of the model. For more information on second position, see the section Working with Two-Position in Chapter 9