A nested AP Div is an AP Div that has code contained within the tags of another AP Div. For example, the following code shows two AP Divs that are not nested, and two AP Divs that are nested:
<div id="apDiv1"></div> <div id="apDiv2"></div> <div id="apDiv3"> <div id="apDiv4"></div> </div>
The graphical depiction for either set of AP Divs might look as follows:
In the first set of div tags, one div is sitting on top of the other on the page. In the second set, the apDiv4 div is actually inside of the apDiv3 div. (You can change AP Div stacking order in the AP Elements panel.)
Nesting is often used to group AP Divs together. A nested AP Div moves with its parent AP Div and can be set to inherit visibility from its parent.
You can enable the Nesting option to automatically nest when you draw an AP Div starting inside another AP Div. To draw inside or over another AP Div, you must also have the Prevent overlaps option deselected.