Fixes missing unit scope

Fixes missing unit scope

Author: chuacw

Demos/Advanced/HeaderCustomDrawDemo.pas

@@ -7,9 +7,11 @@
 interface
 
 uses
-  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
-  Dialogs, ImgList, VirtualTrees, StdCtrls, ExtCtrls, VirtualTrees.BaseTree, System.ImageList,
-  VirtualTrees.Types, VirtualTrees.BaseAncestorVCL, VirtualTrees.AncestorVCL;
+  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
+  System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs,
+  Vcl.ImgList, VirtualTrees, Vcl.StdCtrls, Vcl.ExtCtrls, VirtualTrees.BaseTree,
+  System.ImageList, VirtualTrees.Types, VirtualTrees.BaseAncestorVCL,
+  VirtualTrees.AncestorVCL;
 
 type
   THeaderOwnerDrawForm = class(TForm)

Demos/Advanced/WindowsXPStyleDemo.pas

@@ -11,10 +11,11 @@ interface
 {$warn UNSAFE_CODE off}
 
 uses
-  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
-  Dialogs, VirtualTrees, ImgList, ComCtrls, ToolWin, Menus, StdCtrls, UITypes,
-  System.ImageList, VirtualTrees.Types, Vcl.ExtCtrls,
-  VirtualTrees.BaseAncestorVCL, VirtualTrees.BaseTree, VirtualTrees.AncestorVCL;
+  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Classes, Vcl.Graphics,
+  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, VirtualTrees, Vcl.ImgList, Vcl.ComCtrls,
+  Vcl.ToolWin, Vcl.Menus, Vcl.StdCtrls, System.UITypes, System.ImageList,
+  VirtualTrees.Types, Vcl.ExtCtrls, VirtualTrees.BaseAncestorVCL,
+  VirtualTrees.BaseTree, VirtualTrees.AncestorVCL;
 
 type
   TWindowsXPForm = class(TForm)