We do not show any tasks in dependency view without proper dates. You need to add proper start and dates for the tasks so that it can be shown in dependency view.
You need to click on notes icon in front of the task name to see the associated notes / documents / forum posts for a particular task.
No. You cannot move tasks between projects.
No. It is not possible to set dependencies between taskslist / milestones.
You can make use of the email id – displayed at the bottom of Tasks & Milestones section – to add tasks and attachments to the task.
By default, Open is selected in the Status filter – displayed at the right side of the page. So, you are unable to view the closed tasks. Once you choose, All or Closed option, you will be able to view the closed tasks.
You can mouse over on the task list's name – whose associated tasks are to be saved as a template, click Action button – displayed to the left of the task list name, click Make As Task Template optio
Go to Settings section, click Task Template link and modify the required task template.
Tasks are plotted in the Gantt chart, based on the date.
No. It is not possible to assign material costs and labor costs (hours) for the tasks within a project.
The Task Reminder function is not available in the Free version. It is available only in Premium and Enterprise packages.
In the Tasks and Milestones section, click the Reorder Task List link.

Now drag and drop the task lists in the required order; click the Save Task List order link.

In the Tasks & Milestones section, mouseover the task name and click the right arrow displayed just to the left of the task name. Once done, the task will be set as the sub-task for the one just above it.

If you want set the subtask for a different task, instead of the one just above it, place the task just below the required task using the reorder option and then click the right arrow.

To reorder the task, click Reorder option available below the last task in the list, drag and drop the tasks and click Save Order option.
The client users will be able to see the tasks, whether it is assigned to them or not, only when the task-list to which the tasks are associated is External. Changing the task lists flag will solve this problem.
To change the task lists flag, follow the steps mentioned below:

This updates the flag to External and from now on your clients can view all tasks and task list under this milestone.
Sometimes, the Task List Flag drop-down might not be available in the Edit Task List form because the task-list might have been linked with a milestone. In this case, the milestone's flag must be modified.

The Task Duration in Hours option is available only in the Premium and Enterprise paid plans.
If you are the Portal Owner, go to the Upgrade/Billing section and see whether your projects account is in the Premium or Enterprise plan.
If yes, activate this option from the Settings --> Company Profile --> Edit Profile section.
In the Gantt Chart, only the dated activities are displayed. i.e Tasks, Subtasks and Milestones. Regarding Task-list, it is not displayed in the Gantt Chart because it is not a dated activity.
Resource i.e team members can be assigned to the task but it is not possible to set resource dedication percent to a task.
Example: John will work on Task A from date 1 to date 2 only with a 30% of his working time.
If you are made as the task owner, the clock icon will show-up to the left of the task. Having the clock icon to not show-up is not possible.
The Send Notification Mail option in the Add Task form will be checked by default and changing the default status is not currently possible.
Exporting the milestones alone is not possible in the current system model. If needed, you can export the tasks for all users across projects using the Export option in the My Tasks section.
To add a task to an existing task list:

The completed tasks are not displayed in the task's list view because the default status filter is Open Tasks.
You can see the completed and open tasks by selecting the status filter as All. However, it is not possible to set All as the default status filter option because the customizing option is not supported in Zoho Projects.