So yesterday, aside from an old glibc issue I received another bug report from another of my sons (this one a teenager). He had just used pacman to install game wesnoth and suddenly the simple openbox pipe menu I use in published WDL_Arch64 failed to work (with pop-up error message about xdg_menu line producing incompatible pipe menu format).
Anyway, I checked wesnoth's desktop file under /usr/share/applications and found that simple pipe menu didn't like the 2>&1 used in the desktop file's sh -c 'Execute' command. I just removed that and all seems fine. Haven't thought about 'why' since I don't really know how the openbox 'pipe' works, but clearly it is fine with simply >/dev/null (which is also part of the desktop file Execute command) but not if stderr also sent there...