It never hurts to quote, but the behavior should probably mirror cmd.exe's tab completion, which means that any file or directory name with these characters should be quoted (probably unicode, too):
"' !%&(),;[]^`{}~+="
I've reported this before, but perhaps as a feature request. It actually should be categorized as a bug since TC doesn't put the filename on the command line in a usable format.
Thank you for TC, Christian! I hope this gets fixed.
