public static int getTransparentTitleBarHeight(JRootPane rootPane) {
    Object property = rootPane.getClientProperty("Window.transparentTitleBarHeight");
    if (property instanceof Integer) {
      return (int)property;
    }

    if ("small".equals(rootPane.getClientProperty("Window.style"))) {
      return JBUI.getInt("macOSWindow.Title.heightSmall", 19);
    }
    else {
      return JBUI.getInt("macOSWindow.Title.height", SystemInfo.isMacOSBigSur ? 29 : 23);
    }
  }
public static int getTransparentTitleBarHeight(JRootPane rootPane)