title: How to make a custom outside border for ComboBox with DropDownStyle(DropDownList)
body: <p>i need to draw a custom outside border for ComboBox with  DropDownStyle = DropDownList when the comboBox is active for instance.
  <a href="https://i.stack.imgur.com/3ZM9i.png" rel="nofollow noreferrer">want the combobox to appear like this image</a> </p>
  
  <p>i tried WndProc but it gives error in DropDownList Style.</p>