title: c# Winform Transparent panel issue with form with gradient
body: <p>I have painted with a gradient my winforms. I´m using a panel in one of them with AutoScroll = true. That way, I can display all the info without taking to much space.</p>
  
  <p>Now, I want that panel to be transparent. I use transparent as background color and works fine. The problem is when I scroll. The transparency messes up. Is there any way to solve this problem? </p>
  
  <p>I also tried to paint the panel with the same gradient that my form has after knowing the final height. But I have the same problem.</p>
  
  <p>Here are some images: (don´t look at the textboxes or those transparent small panels. That will be white).</p>
  
  <p>Before scrolling (RIGHT)
  <img src="https://i.stack.imgur.com/wW4rP.png" alt="enter image description here"></p>
  
  <p>After scrolling (Backcolor issue)
  <img src="https://i.stack.imgur.com/xJcU7.png" alt="enter image description here"></p>
  
  <p>Another one after scrolling:</p>
  
  <p><img src="https://i.stack.imgur.com/vhru8.png" alt="enter image description here"></p>