Account for taskbar on different display

File-New-Project#1611

Author: Simplestas

EarTrumpet/Interop/Helpers/WindowsTaskbar.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Drawing;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Windows.Forms;
@@ -43,7 +44,7 @@ public static State Current
                 var appBarData = new APPBARDATA
                 {
                     cbSize = (uint)Marshal.SizeOf(typeof(APPBARDATA)),
-                    hWnd = hWnd
+                    lParam = 0x42 // magic to get StartAllBack active taskbar rect
                 };
 
                 // SHAppBarMessage: Understands Taskbar auto-hide
@@ -52,6 +53,10 @@ public static State Current
                 {
                     state.Size = appBarData.rect;
                     state.Location = (Position)appBarData.uEdge;
+                    var r = new Rectangle(appBarData.rect.Left, appBarData.rect.Top,
+                        appBarData.rect.Right - appBarData.rect.Left,
+                        appBarData.rect.Bottom - appBarData.rect.Top);
+                    state.ContainingScreen = Screen.FromRectangle(r);
                 }
                 else
                 {