Thread:Pecoes/@comment-188432-20130323152516/@comment-3508190-20130325043327

They have different contexts:
 * add the new element inside of the reference element.
 * add the new element next to the reference element.

Example:

To get from this:

to this:

You could either:
 * use  on the   or
 * use  on the

(In this simple example it doesn't matter which method you choose, of course)