Look of arrows to submenus is non-native and confusing

When a menu contains sub-menus, there are small arrows pointing to those:

In Qt (here: Qt 5.11.2), they already look different than the native ones (QTBUG-71372):

In Qt Creator (built on the same Qt version) it's even worse, because here the arrows always look the same, regardless of whether the sub-menu is enabled or not:

There should at least be a visual difference between these arrows with an enabled and a disabled sub.menu again.