,
I don't know the exact algorithms used when LabVIEW places a control or indicator on the front panel, but I can tell you what I have observed so far:
It seems that the new controls and indicators are always placed below all other controls and indicators. There may be additional rules, but this seems to be the most common occurrence I have seen.
If you want more control over where your controls and indicators are placed, then you should created them manually from the palette before you begin your diagram. This is good practice, but not always possible.
I hope that helps. Good luck.