Если прозрачная часть glyph'а становится видной...

Code:

function InitStdBitBtn(BitBtn: TBitBtn; kind: TBitBtnKind): bool;

var

Bm1: TBitmap;

Bm2: TBitmap;

begin

Result := false;

if Kind = bkCustom then

   exit;

Bm1 := TBitmap.Create;

case Kind of

   bkOK: Bm1.Handle := LoadBitmap(hInstance, 'BBOK');

   bkCancel: Bm1.Handle := LoadBitmap(hInstance, 'BBCANCEL');

   bkHelp: Bm1.Handle := LoadBitmap(hInstance, 'BBHELP');

   bkYes: Bm1.Handle := LoadBitmap(hInstance, 'BBYES');

   bkNo: Bm1.Handle := LoadBitmap(hInstance, 'BBNO');

   bkClose: Bm1.Handle := LoadBitmap(hInstance, 'BBCLOSE');

   bkAbort: Bm1.Handle := LoadBitmap(hInstance, 'BBABORT');

   bkRetry: Bm1.Handle := LoadBitmap(hInstance, 'BBRETRY');

   bkIgnore: Bm1.Handle := LoadBitmap(hInstance, 'BBIGNORE');

   bkAll: Bm1.Handle := LoadBitmap(hInstance, 'BBALL');

end;

Bm2 := TBitmap.Create;

Bm2.Width := Bm1.Width;

Bm2.Height := Bm1.Height;

Bm2.Canvas.Brush.Color := ClBtnFace;

Bm2.Canvas.BrushCopy(Rect(0, 0, bm2.Width, bm2.Height), Bm1,

   Rect(0, 0, Bm1.width, Bm1.Height),

   Bm1.canvas.pixels[0, 0]);

Bm1.Free;

LockWindowUpdate(BitBtn.Parent.Handle);

BitBtn.Kind := kind;

BitBtn.Glyph.Assign(bm2);

LockWindowUpdate(0);

Bm2.Free;

Result := true;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

InitStdBitBtn(BitBtn1, bkOk);

end;