C# application - system transparent control inside user drawn control...

[MasterOfTheDark]

This one's a hairy one to explain. What I've got is a class called "VistaGroupBox" that I put some nice-looking Vista-style gradients in the background and made to look like the ribbon categories you see in Office 2007. I got it working great, and created a few more controls, including a "VistaButton", which is primarily transparent when the cursor does not hover over it. However, when I added a standard Panel in the VistaGroupBox and put my button inside the Panel (I want the Panel to auto-scroll), the VistaButton's transparent background started as though it were in the upper-left-hand corner of the VistaGroupBox, which was not where the button actually was at all! The button draws correctly when outside the Panel.

So, what I've got is this:

VistaGroupBox
 +-Panel
    +-VistaButton

In order to draw my transparent controls, I've made a function that does this: (Some controls, like Button, don't have transparency support at all - I got this from the Mono implementation)

        public delegate void InvokePaintDelegate(Control c, PaintEventArgs e);
        public delegate void InvokePaintBackgroundDelegate(Control c, PaintEventArgs e);
        /// <summary>
        /// This function looks like a mess primarily because of the #if ... #endifs.  The problem is, the "BROKEN WINDOWS"
        /// section is how WINDOWS does it, which is a problem for going through multiple transparent areas for whatever reason.
        /// MY_CORRECT works if you're only going from user drawn transparency to user drawn transparency - that is, none of your
        /// controls use Control.OnPaintBackground (like a Transparent Panel).  WINDOWS_HACK works in all conditions - too bad it uses
        /// a bit more memory due to the image creation.
        /// </summary>
        /// <param name="c">The control to paint the parent to</param>
        /// <param name="pevent">The PaintEventArgs from the OnPaintBackground call</param>
        /// <param name="InvokePaint">The control's InvokePaint method - because it is protected.</param>
        /// <param name="InvokePaintBackground">The control's InvokePaintBackground method - because it is protected.</param>
        public static void DrawParent(Control c, PaintEventArgs pevent, InvokePaintDelegate InvokePaint, InvokePaintBackgroundDelegate InvokePaintBackground)
        {
            PaintEventArgs parent_pe;
            GraphicsState state;
            Rectangle clipRect;
 
            Graphics g;
#if BROKEN_WINDOWS
            IntPtr hdc = pevent.Graphics.GetHdc();
            g = Graphics.FromHdc(hdc);
            if (c.Region != null)
                g.Clip = c.Region;
            else
                g.Clip = new Region(c.ClientRectangle);
            clipRect = new Rectangle(pevent.ClipRectangle.X + c.Left, pevent.ClipRectangle.Y + c.Top, pevent.ClipRectangle.Width, pevent.ClipRectangle.Height);
#elif MY_CORRECT
            g = pevent.Graphics;
            clipRect = new Rectangle(pevent.ClipRectangle.X + c.Left, pevent.ClipRectangle.Y + c.Top, pevent.ClipRectangle.Width, pevent.ClipRectangle.Height);
#elif WINDOWS_HACK
            Image img = new Bitmap(c.Parent.Width, c.Parent.Height, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
            g = Graphics.FromImage(img);
            clipRect = new Rectangle(c.Location, c.Size);
            g.Clip = new Region(clipRect);
#endif
 
            parent_pe = new PaintEventArgs(g, clipRect);
 
            state = g.Save();
#if !WINDOWS_HACK
            g.TranslateTransform(-c.Left, -c.Top);
#endif
            InvokePaintBackground(c.Parent, parent_pe);
            g.Restore(state);
 
            state = g.Save();
#if !WINDOWS_HACK
            g.TranslateTransform(-c.Left, -c.Top);
#endif
            InvokePaint(c.Parent, parent_pe);
            g.Restore(state);
 
#if BROKEN_WINDOWS
            g.Dispose();
            pevent.Graphics.ReleaseHdc(hdc);
#elif WINDOWS_HACK
            g.Dispose();
            pevent.Graphics.DrawImage(img, new Rectangle(new Point(0,0), c.Size), new Rectangle(c.Location, c.Size), GraphicsUnit.Pixel);
            img.Dispose();
#endif
        }
 

You can see that I've got 3 preprocessor directives here, each should be used exclusively. BROKEN_WINDOWS behaves exactly like the Windows default, WINDOWS_HACK works properly, except I'm creating images, and so it tends to be a bit slow.

Anyone got some time to help me figure this one out?