As a user, it is confusing behavior that the QtQuick items nested in an ApplicationWindow do not all respect the system settings for Day/Night mode.  What this creates is a scenario where some text is visible, and some text is not in Dark Mode because Text QML object have a default color of black.  It seems that all Qt types that display visible text should follow app pallettes.  Here are some screen shots:

Note the missing text labels on the sliders.