border makes child's margin be included in parents size

by shahryar saljoughi

HTML

<!-- I can see that border affects the fact that childs margin contributes to parrents height or not -->

<div id="parent1">
<P >
this is some text
</P>
</div>

<div id="parent2">
<p >
this is some text
</p>
</div>

CSS

#parent1 {
  background-color: red;
  border: dotted;
}
#parent2 {
  background-color: yellow;
}