I have been scratching my head over this one for a while (since version 6 came out).
Once I have started mirc, I keep my windows tiled. I have 5 of them. Listed from bottom to top:

ch 1
ch 2
ch 3
status
ch 4

Prior to version 5, the order would be:

status
ch 1
ch 2
ch 3
ch 4

How do I get the status window to STAY on the bottom?

Window - Group - Group windows by network.

Try different items checked/unchecked until you find the situation you like best.
Personally, I have all except for the top two checked.

Thank you Russell!!!

I now have just the last two checked as well, and my status window is on the bottom.

Thanks for solving the riddle.

Lou