This behavior is not scheduled to be addressed. Part of the issue is that Test Studio is designed to always clear the text before setting the new one. Part of the clear textbox procedure is to call keyPress for the 'End' key which unfortunately moves the selection to the last item. If this issue is negatively effecting your automation efforts, I recommend adding your experience to the public feedback item
Although this won't be an issue in every case, we recommend setting SimulateRealUser to false when necessary.