title: Mouse up event doesn't get triggered
body: <p>I have the following problem: I have a panel which has a specific color, say red.
  When the user presses his mouse, the color of this panel gets stored in a variable. Then the user moves, his mouse still pressed, over to another panel. When he releases the mouse there, this panel should get the background color of the first that had been stored in the variable. My code looks something like this:</p>
  
  <pre><code>    public Color currentColor;
      private void ColorPickMouseDown(object sender, MouseEventArgs e)
      {
          Panel pnlSender = (Panel)sender;                   
          currentColor = pnlSender.BackColor;
      }
  
      private void AttempsColorChanger(object sender, MouseEventArgs e)
      {
          Panel pnl = (Panel)sender;
          pnl.BackColor = currentColor;
      }
  </code></pre>
  
  <p>I need to identify the sender first because there are many possible panels that can trigger this event. The first MouseDown method works totally fine, the color is stored nicely in the variable. The secon one however doesn't even get triggered when the user does what I described above. When the ser clicks on the second panel, it works (there is an MouseUp part in a click aswell I guess).</p>
  
  <p>What's wrong here? Why is the event not triggered when the user holds the mouse key down before?</p>