title: How to tell if Shift is being pressed in a MouseDown event?
body: <p>I am catching a <code>MouseDown</code> event on a control, which gives me a <code>MouseEventArgs</code> object in the signature. Now I want to be able to tell if the user was holding down the "Shift" or "Control" key when they clicked. But the <code>MouseEventArgs</code> object doesn't contain any keyboard information!</p>
  
  <p>What's the easiest way of telling whether the keyboard <kbd>Shift</kbd>/<kbd>Ctrl</kbd> keys were being held at the time of the click?</p>