Revert "Fix #644: still use focusable window on Windows 7 and 8"

This reverts commit 452574e.

Revert "Fix #644 step 1: correctly bring window back to top when clicked"

This reverts commit af608dc.

QuickLook/ViewerWindow.xaml.cs

@@ -18,13 +18,14 @@
 using System;
 using System.Windows;
 using System.Windows.Input;
-using System.Windows.Interop;
-using System.Windows.Media;
 using System.Windows.Media.Animation;
 using QuickLook.Common.ExtensionMethods;
 using QuickLook.Common.Helpers;
 using QuickLook.Common.Plugin;
 using QuickLook.Helpers;
+using Brush = System.Windows.Media.Brush;
+using FontFamily = System.Windows.Media.FontFamily;
+using Size = System.Windows.Size;
 
 namespace QuickLook
 {
@@ -54,14 +55,8 @@ internal ViewerWindow()
 
  StateChanged += (sender, e) => _ignoreNextWindowSizeChange = true;
 
- // bring the window to top when users click in the client area.
- // the non-client area is handled by the WndProc inside OnSourceInitialized().
- // This is buggy for Windows 7 and 8: https://github.com/QL-Win/QuickLook/issues/644#issuecomment-628921704
- if (App.IsWin10)
- PreviewMouseDown += (sender, e) => this.BringToFront(false);
-
  windowFrameContainer.PreviewMouseMove += ShowWindowCaptionContainer;
-
+ 
  Topmost = SettingHelper.Get("Topmost", false);
  buttonTop.Tag = Topmost ? "Top" : "Auto";
 
@@ -103,32 +98,6 @@ internal ViewerWindow()
  buttonOpenWith.Click += (sender, e) => ShareHelper.Share(_path, this, true);
  }
 
- // bring the window to top when users click in the non-client area.
- protected override void OnSourceInitialized(EventArgs e)
- {
- base.OnSourceInitialized(e);
-
- // The non-focusable trick is buggy for Windows 7 and 8
- // https://github.com/QL-Win/QuickLook/issues/644#issuecomment-628921704
- if (App.IsWin10)
- {
- this.SetNoactivate();
-
- HwndSource.FromHwnd(new WindowInteropHelper(this).Handle)?.AddHook(
- (IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled) =>
- {
- switch (msg)
- {
- case 0x0112: // WM_SYSCOMMAND
- this.BringToFront(false);
- break;
- }
-
- return IntPtr.Zero;
- });
- }
- }
-
  public override void OnApplyTemplate()
  {
  base.OnApplyTemplate();