The fieldset's border drawing display item shouldn't participate in hit-testing. That's handled by its background item already. Upstreamed from https://bugzilla.mozilla.org/show_bug.cgi?id=1326163 
diff --git a/cssom-view/elementFromPoint.html b/cssom-view/elementFromPoint.html index c530064..20d3077 100644 --- a/cssom-view/elementFromPoint.html +++ b/cssom-view/elementFromPoint.html 
@@ -52,6 +52,19 @@  <area id="rectG" shape="rect" coords="0,0,90,100" href="#" alt="area 1"/>  <area id="circleO" shape="circle" coords="120,60,30" href="#" alt="area 2"/>  <area id="polyLE" shape="poly" coords="280,0,310,0,360,30,360,90,280,90" href="#" alt="area 3"/> + <!-- Test for fieldsets not doing weird things. Use a 200x200 div to hold + all the bits for this test. Also, place it top/right, so it is not below + the bottom edge of the viewport. --> + <div style="position: absolute; width: 200px; height: 200px; right: 0; top: 0"> + <div id="fieldset-div" + class="size" style="position: absolute; top: 0; left: 0"> + </div> + <fieldset class="size" style="position: absolute; top: 100px; left: 100px"> + <!-- Place the child span so the overflow area of the fieldset overlaps + the div --> + <span style="position: absolute; top: -100px; left: -100px; height: 1px; width: 1px"></span> + </fieldset> + </div>  <script>  setup({explicit_done:true});  window.onload = function () { @@ -168,6 +181,15 @@  image,  "Should have returned the image element");  }, "Image Maps"); + + test(function(){ + var fieldsetDiv = document.getElementById("fieldset-div"); + var divRect = fieldsetDiv.getBoundingClientRect(); + assert_equals(document.elementFromPoint(divRect.left + divRect.width/2, + divRect.top + divRect.height/2), + fieldsetDiv, + "The fieldset should not cover up the div it doesn't even overlap"); + }, "Fieldsets");  done();  }  </script>