So you know how if you right click on your desktop, the menu will appear either at the top-left, top-right, bottom-left, bottom-right depending on where your cursor is on the page? (
<select> elements do the same.)
Is there a name for that?
The menu you're talking about is a contextual menu. http://en.wikipedia.org/wiki/Context_menu
I believe the type of positioning you're talking about is called relative positioning