manual/include/separate-under.html

<p>
  You may have a situation where you have positioned one region over another, 
  and you just want to cut the lower region so that it directly adjoins both 
  ends of the overlapping one, with no overlaps. To do this, select the upper 
  region, then choose <kbd class="menu">Edit &gt; Separate &gt; Separate
  Under</kbd>. This will split the lower region so that it no longer overlaps 
  the upper region at all. <br />
  Here is an example where we start with a short region placed so that it 
  overlaps a longer region:
</p>
<img src="/images/a3_before_separate_under.png" alt="region arrangement before separate under" />
<p>
  When we perform the <dfn>Separate Under</dfn> edit, the lower region splits 
  in two, with boundaries exactly positioned at the edges of the upper region:
</p>
<img src="/images/a3_after_separate_under.png" alt="region arrangement after separate under" />
<p>
  If the upper region covers only one end of the lower region, then this 
  operation is equivalent to 
  <a href="/editing-and-arranging/change-region-lengths/#trimtonextprevious">Trim to Next or Trim to Previous</a>, 
  depending on which end is covered.
</p>