QML/JS formatter does not respect tab/space indentation settings

When using a custom profile that forces tabs in QtCreator (Settings > QtQuick section > new profile > "Only tabulations"), the formatter always emits spaces for indentation.

As far as I can see all the other QML editing features respect the setting (previews use tabs, typing my Tab key enters a tabylation in the editor, etc.). But the moment I hit the QML reformatter, all my tabs are changed back into spaces.

I expect the formatter to respect the tab/space setting defined by the user.