Preview changes: (1) when define later activity occurs don't tell the tool that it is define later but display a special screen before going to the next tool (2) for chosen grouping, schedule and permission gates show the normal page with an extra preview message then override the normal process and continue.
Grouping failing when max number of groups null - now allows any number of groups. Also changed the calculation of urls so that " null + some parameter" = null rather than null?param=blah