https://bugs.winehq.org/show_bug.cgi?id=54141
--- Comment #3 from Eric Pouech eric.pouech@gmail.com --- that looks like a key binding issue: - in a blank xterm, at unix shell prompt (no wine invocation), does also ctrl-4 close the xterm windows?
(that's a behavior I would expect from ctrl-F4 but not from ctrl-4)