title: Why is onMouseUp not firing?
body: <p>I have a div, with an onMouseUp event set (in HTML). 
  Within that div are many elements, some of which contain icons for handles that I want to drag. 
  The icons have an onMouseDown event. </p>
  
  <p>When I drop the mouse on an icon and release it, first the icon's onMouseDown event fires, then the div's onMouseUp event fires - exactly as I would expect. </p>
  
  <p>However when I click down on the icon, drag it to another part of the div, and release, the mouseDown event is fired as you would expect, and the onmouseUp event is NOT fired. </p>
  
  <p>I have two questions. </p>
  
  <p>1) Why is this the behaviour?</p>
  
  <p>2) What is the correct way to handle drag-drop in a browser independant way? </p>
  
  <p>I am using firefox 3.6.16 on widows, but IE 8 behaves the same way. </p>