Close all windows on Application close, not just main one

src/TestStack.White/Application.cs

@@ -10,6 +10,7 @@
 using TestStack.White.Sessions;
 using TestStack.White.UIItems.Finders;
 using TestStack.White.UIItems.WindowItems;
+using TestStack.White.WindowsAPI;
 
 namespace TestStack.White
 {
@@ -215,7 +216,10 @@ public virtual void Close()
                 Process.Dispose();
                 return;
             }
-            Process.CloseMainWindow();
+            foreach (var window in NativeWindow.GetProcessWindows(Process.Id))
+            {
+                window.PostCloseMessage();
+            }
             Process.WaitForExit(5000);
             if (!Process.HasExited)
             {

src/TestStack.White/WindowsAPI/NativeWindow.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Runtime.InteropServices;
 using System.Windows;
 
@@ -20,6 +21,43 @@ public class NativeWindow
         [DllImport("gdi32.dll")]
         private static extern COLORREF GetTextColor(IntPtr hdc);
 
+        [DllImport("user32.dll")]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        private static extern bool EnumWindows(EnumWindowsProc lpEnumFunc, IntPtr lParam);
+
+        private delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);
+
+        [DllImport("user32.dll", SetLastError = true)]
+        private static extern uint GetWindowThreadProcessId(IntPtr hWnd, out int lpdwProcessId);
+
+        [DllImport("user32.dll")]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        private static extern bool IsWindowEnabled(IntPtr hWnd);
+
+        [return: MarshalAs(UnmanagedType.Bool)]
+        [DllImport("user32.dll", SetLastError = true)]
+        private static extern bool PostMessage(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
+
+        private const uint WM_CLOSE = 0x0010;
+
+        public static IEnumerable<NativeWindow> GetProcessWindows(int processId)
+        {
+            var result = new List<NativeWindow>();
+            Func<IntPtr, bool> processWindow = hwnd =>
+            {
+                if (IsWindowEnabled(hwnd))
+                {
+                    int pid;
+                    GetWindowThreadProcessId(hwnd, out pid);
+                    if (pid == processId)
+                        result.Add(new NativeWindow(hwnd));
+                }
+                return true;
+            };
+            EnumWindows((wnd, param) => processWindow(wnd), IntPtr.Zero);
+            return result;
+        }
+
         public NativeWindow(Point point)
         {
             handle = WindowFromPoint(new POINT((int) point.X, (int) point.Y));
@@ -45,5 +83,10 @@ public virtual COLORREF TextColor
                 return GetTextColor(GetDC(handle));
             }
         }
+
+        public virtual void PostCloseMessage()
+        {
+            PostMessage(handle, WM_CLOSE, IntPtr.Zero, IntPtr.Zero);
+        }
     }
-}
+}