Field mPopup = popupMenu.getClass().getDeclaredField("mPopup");
mPopup.setAccessible(true);
MenuPopupHelper helper = (MenuPopupHelper) mPopup.get(popupMenu);
Class standardMenuPopup = Class.forName("androidx.appcompat.view.menu.StandardMenuPopup");
Field mPopupField = standardMenuPopup.getDeclaredField("mPopup");
mPopupField.setAccessible(true);
MenuPopupWindow menuPopupWindow = (MenuPopupWindow) mPopupField.get(helper.getPopup());
menuPopupWindow.getListView().setSelector(background);