procedure SetVistaFonts(const AForm: TCustomForm);
begin
  if (IsWindowsVista or not CheckOSVerForFonts)
    and not SameText(AForm.Font.Name, VistaFont)
    and (Screen.Fonts.IndexOf(VistaFont) >= 0) then
  begin
    AForm.Font.Size := AForm.Font.Size + 1;
    AForm.Font.Name := VistaFont;
  end;
end;

procedure SetDefaultFonts(const AFont: TFont);
begin
  AFont.Handle := GetStockObject(DEFAULT_GUI_FONT);
end;

procedure SetDesktopIconFonts(const AFont: TFont);
var
  LogFont: TLogFont;
begin
  if SystemParametersInfo(SPI_GETICONTITLELOGFONT, SizeOf(LogFont),
    @LogFont, 0) then
    AFont.Handle := CreateFontIndirect(LogFont)
  else
    SetDefaultFonts(AFont);
end;

procedure SetVistaContentFonts(const AFont: TFont);
begin
  if (IsWindowsVista or not CheckOSVerForFonts)
    and not SameText(AFont.Name, VistaContentFont)
    and (Screen.Fonts.IndexOf(VistaContentFont) >= 0) then
  begin
    AFont.Size := AFont.Size + 2;
    AFont.Name := VistaContentFont;
  end;
end;

procedure SetVistaTreeView(const AHandle: THandle);
begin
  if IsWindowsVista then
    SetWindowTheme(AHandle, 'explorer', nil);
end;

procedure TMainForm.WMActivate(var Message: TWMActivate);
begin
  if (Message.Active = WA_ACTIVE) and not IsWindowEnabled(Handle) then
  begin
    SetActiveWindow(Application.Handle);
    Message.Result := 0;
  end else
    inherited;
end;

if IsWindowVisible(Wnd) and 

  ((GetWindowLong(Wnd, GWL_HWNDPARENT) = 0) or
  (HWND(GetWindowLong(Wnd, GWL_HWNDPARENT)) = GetDesktopWindow)) and
  ((GetWindowLong(Wnd, GWL_EXSTYLE) and WS_EX_TOOLWINDOW) = 0) then
begin
  ...
end;

if IsWindowVisible(Wnd) and 

  ((GetWindowLong(Wnd, GWL_HWNDPARENT) = 0) or
  (HWND(GetWindowLong(Wnd, GWL_HWNDPARENT)) = GetDesktopWindow)) then
begin
  ...
end;