1. I cannot expand and see tasks present in my taskslist ?

When you click on Collapse Tasklist link this takes precedence to individual expand option of each tasklist. For this you need click on the Expand Taskslist link present in the top panel and this will expand all your taskslist.

2. I added tasks but they are not visible in task dependency view?

We do not show any tasks in dependency view without proper dates. You need to add proper dates for the tasks so that it can be shown in dependency view.

3. How can I see notes / documents / forum posts associated for a task?

You need to click on yellow colored icon in front of the task name to see the associated notes / documents / forum posts for a particular task.

4. Can I move tasks between projects?

No. You cannot move tasks between projects.

5. Is it possible to set dependency between taskslist / milestones?

No. It is not possible to set dependencies between taskslist / milestones.