Log in to the HTML5 client.
Select the Work workspace, Gantt tab.
Select a project in the Project Data Selector.
Place the mouse pointer on the right-hand side of the task’s Start Date or on the right-hand side of the date on which its progress was entered and hold down the Shift key to visualize the Split (
) icon.
Hold down the left mouse button and extend the completed portion of the task to the desired date.