What makes a task critical? I was thinking maybe it was related to predecessors and successors, but I have some that are marked critical without them...
A critical task is one which if delayed, would delay the entire project.
This article on CPM scheduling should shed some light: http://en.wikipedia.org/wiki/Critical_path_method
Good article. I actually meant to ask what makes a task critical in OpenProj? Several of my tasks in the GANTT chart are red, and I can't figure out why.