1) You can change the behavior of the tab key in OmniPlan > Preferences > General
2) Yes, you have to change the end date independent of changing percent done if your real world end date doesn't match your plan. A few other features do auto-adjust for current time though. "Catch up" and "Reschedule"
3) Not sure what exactly is going on. It'd be easier if you sent us your file or at least a screenshot to
omniplan@omnigroup.com
4) select those two tasks and option-click "Connection"; or select one of the tasks, go to the Task: Dependencies inspector, and click the gray x next to the other task.
5) Not sure. send us your file?
6) OmniPlan will not level tasks that have violations (the red stop sign with a hand on it). Also, if you have 200% units on your resource, or you're only assigned to each task at 50%, OmniPlan thinks you
can do both those tasks at the same time.