By default the dropdown renders floating above the rest of your page but it doesn't prevent the user from clicking on any other item. Overlays can fix that and make dropdowns look cooler.
What do you have to know:
By default overlays have a semitransparent black background, but you can change that
$ember-basic-dropdown-overlay-backgroundSASS variable or target the
By default overlays have
pointer-events: none, so it is transparent to clicks but you can change that using the
$ember-basic-dropdown-overlay-pointer-eventsSASS variable or target the same class.
In the next section we'll talk more how to customize the styles.