Hi I solved the issue starting all other kix scripts with a .bat file.
After analysing this I'd say RunOnce entries are either always executed before the shell starts up or .kix extension are always seen as part of a login script (since we've got 'Run login scripts synchronously' activated).
Starting these scripts with a .bat or .cmd file tricks the OS into thinking all scripts have been executed and is allowed to start up the shell.

David