After rebuilding the Launch Services,
`/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain user;killall Finder;echo "Open With has been rebuilt, Finder will relaunch" `
I got the same behavior as reported by techee. That is, double-clicking a file now opens a new instance of Geany 1.36.
Still a problem -- but we see the same thing.