TTabSheet =  class (ComCtrls.TTabSheet)
 // Тупо перенесенный код из TCustomControl 
   private 
    FCanvas: TCanvas;
     procedure  WMPaint( var  Message: TWMPaint); message WM_PAINT;
   protected 
     procedure  PaintWindow(DC: HDC); override;
     property  Canvas: TCanvas read FCanvas;
   public 
     constructor  Create(AOwner: TComponent); override;
     destructor  Destroy; override;
 end ;

  TForm1 =  class (TForm)
    PageControl1: TPageControl;
    TabSheet1: TTabSheet;
    TabSheet2: TTabSheet;
    Panel1: TPanel;
     procedure  PageControl1DrawTab(Control: TCustomTabControl;
      TabIndex: Integer;  const  Rect: TRect; Active: Boolean);
     procedure  FormCreate(Sender: TObject);
   private 
     { Private declarations } 
   public 
     { Public declarations } 
   end ;

 var 
  Form1: TForm1;

 implementation 

 {$R *.dfm} 

 type 
THask =  class (TPageControl);
 procedure  TForm1.FormCreate(Sender: TObject);
 begin 
  THask(PageControl1).Color := clBlue;
 end ;

 procedure  TForm1.PageControl1DrawTab(Control: TCustomTabControl;
  TabIndex: Integer;  const  Rect: TRect; Active: Boolean);
 begin 
  Control.Canvas.Brush.Color := clRed;
  Control.Canvas.FillRect(Rect);
 end ;

 { TTabSheet } 

 constructor  TTabSheet.Create(AOwner: TComponent);
 begin 
   inherited  Create(AOwner);
  FCanvas := TControlCanvas.Create;
  TControlCanvas(FCanvas).Control := Self;
 end ;

 destructor  TTabSheet.Destroy;
 begin 
  FCanvas.Free;
   inherited  Destroy;
 end ;

 procedure  TTabSheet.PaintWindow(DC: HDC);
 begin 
  FCanvas.Lock;
   try 
    FCanvas.Handle := DC;
     try 
      TControlCanvas(FCanvas).UpdateTextFlags;

      FCanvas.Brush.Color := clRed;
      fCanvas.FillRect(ClientRect);
     finally 
      FCanvas.Handle :=  0 ;
     end ;
   finally 
    FCanvas.Unlock;
   end ;
 end ;

 procedure  TTabSheet.WMPaint( var  Message: TWMPaint);
 begin 
  ControlState := ControlState + [csCustomPaint];
   inherited ;
  ControlState := ControlState - [csCustomPaint];
 end ;