[baijuxavior]

Did you try the option 'Focus External Player'? under 'External Players and Focus' menu?

---

It's what I tried yes, but after reading half of this wole thread today I understand that I haven't followed the good idea.

New test tonight using "External Apps Group 1' tab, added Steam.exe on Application 1 and check "Prevent XBMC Focus"
Solved the Focus part of my problem.

I now just need to add an exception on the script because as I need the "Start Metro UI when XBMC is closed" option, Metro UI is launched allongside to Steam when exiting XBMC and this Metro UI take focus ...

Is it possible to add an exception of that kind ?

Line No. 1691 is for starting metro ui when xbmc is closed. You can add a line to check for steam and if it is running skip the code.

Code:

Process, Exist, xbmc.exe ; check if xbmc.exe is running
If (ErrorLevel = 0) ;if not running
    Process, Exist, steam.exe ; check if steam.exe is running
    If (ErrorLevel = 0)
        {
                    Process, Exist, explorer.exe ; check if explorer.exe is running
                    If (ErrorLevel = 0)