What about including the output of

$ GNUPGHOME=/tmp/foo gpgconf -L homedir
/tmp/foo

in the getWindowName() function. Or to better handle long homedirs with strange characters to use something like

$ GNUPGHOME=/tmp/foo gpgconf -L socketdir | sed 's,.*/d\.,,'
e4eiyium4hwx3rfwiz5r1won

which gives the hash of the homedir if it is not the default one. First do a test to see whether there is really a hash (ie. a non-standard GNUPGHOME). Thus if you find a slash or backslash in the output of the abaove do not extend the window name.

After discussion with Ingo and others it seems that separate Kleo processes per GNUPGHOME would confuse more users than being helpful for power users. Considering the use case of gpgpass the conclusion was to add an option to Kleo which allows to start is as a certificate manager without doing the UniqueApplicaiton thing and also entirely quit after closing the window.