This window has 2 parts: a title bar and the navigation tabs.

• The title bar tells you where you are in AceProject. At the end of the title bar you will find links to the contextual help, to add a new task, to open or close an IN/OUTwork item, to move/copy a task, and to a printer-friendly version of the page. 
• The Task tab displays the main task information.
• The Assignment tab shows which users are assigned or reviewers on the task.
  • Simply check the boxes next to the users who will be assigned and/or reviewers on the task.
  • You can select as many assigned users or reviewers as you want.
  • You can un-assign the users simply by un-checking the corresponding boxes.
  • Whenever an assignment change is made, the task's Last Update will be adjusted accordingly.
  • Check the "Do not send email notification" box to avoid sending an email if the update does not warrant it.
  • Click the "Update" button to save your changes or click the down arrow to expand a drop-down list that will let you perform the following actions:
    • "Update + Edit Task" lets you save your changes and reach the "Task" tab.
    • "Update + Attach Files" lets you save your changes and reach the "File Attachment(s)" tab.
    • "Update + Set Dependencies" lets you save your changes and reach the "Dependencies" tab.
    • "Update + View History" lets you save your changes and reach the "History Trail" tab.
    • "Update + Go to Previous Task" lets you save your changes and open the previous task in the list.
    • "Update + Go to Next Task" lets you save your changes and open the next task in the list.
  • Click the "Back" button to return to the "Tasks" page without saving anything. 
• The File Attachments tab shows all files that are attached to this task. Attachments can be documents, screen captures or any other file format. Click this tab to view all attached files or upload new ones to this task.
• The Dependencies tab displays all relationships between this task and other tasks in that project.
• The History Trail tab displays all changes that have been performed on the task since it's been created.
• The Prev. Task link lets you open the previous task in the list.
• The Next Task link lets you open the next task in the list.

How do I remove/un-assign a user from a task?
To un-assign users from a task, simply un-check the corresponding boxes and click the "Update" button.