Source/PopupShadow.cs

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using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Drawing.Imaging;

namespace DevComponents.DotNetBar
{
	/// <summary>
	/// Summary description for PopupShadow.
	/// </summary>
	internal class PopupShadow : System.Windows.Forms.Control
	{
		private bool m_AlphaShadow=true;
		public PopupShadow(bool bAlphaShadow)
		{
			m_AlphaShadow=bAlphaShadow;
			this.Visible=false;
			this.SuspendLayout();
			if(!m_AlphaShadow)
				this.BackColor=SystemColors.ControlDark;
			//this.ControlBox = false;
			//this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
			//this.MaximizeBox = false;
			//this.MinimizeBox = false;
			//this.Opacity = 0.4;
			//this.ShowInTaskbar = false;
			//this.AutoScale=false;
			this.Size=new Size(12,12);
			//this.StartPosition=FormStartPosition.Manual;
			//this.MinimumSize=new Size(4,4);  // This was the key to fix the black box that was showing up for smaller windows

			this.SetStyle(ControlStyles.ContainerControl,false);
			//this.TopLevel=false;

			this.SetStyle(ControlStyles.Selectable,false);
			if(m_AlphaShadow)
			{
				this.SetStyle(ControlStyles.AllPaintingInWmPaint,true);
				this.SetStyle(DisplayHelp.DoubleBufferFlag,false);
			}
			this.ResumeLayout();
		}

		protected override void OnHandleCreated(EventArgs e)
		{
			base.OnHandleCreated(e);
            //NativeFunctions.SetLayeredWindowAttributes(this.Handle,Color.Black.ToArgb(),102,NativeFunctions.LWA_ALPHA);
			// We want to make the entire bitmap opaque 
		}
		
		private void PaintShadow()
		{
            if(this.Width <= 0 || this.Height <= 0) return;

			// Create bitmap for drawing onto
			Bitmap memoryBitmap = new Bitmap(this.Width, this.Height, PixelFormat.Format32bppArgb);

			using(Graphics g = Graphics.FromImage(memoryBitmap))