Calendar overlays allow you to create a combined view of your Calendars and/or To Do Lists by layering more Calendars or To Do Lists on top. If you assign dates to your Tasks on your lists you can create an overlay to use on your Calendars. This way you can view all of your Tasks and Events at once to make sure you never miss a date for a Task.
Hiding To Do Lists as a Calendar overlay
If you no longer want to view your To Do List tasks on your calendar, you can click on the checkbox next to the name of your To Do List in the Navigator to turn your list off from showing on the calendar. See the image below:
Removing To Do Lists as a Calendar overlay
If you don't want to just hide your To Do List from showing on your calendar you can also remove your To Do List overlay completely. Removing the To Do List as an overlay doesn't have any other effect on your list. You can still access the list from your To Do application. See the image below: