dfaure added a comment.
Looking at the code in qxcbintegration.cpp, it seems that WM_CLASS is in fact derived from 1. -name xcb-specific commandline argument, let's ignore that 2. $RESOURCE_NAME env var, no idea what that is, let's ignore that 3. the basename of argv[0], i.e. the name of the executable. kmail's executable is called kmail. This is then followed by QCoreApplication::applicationName which is indeed "kmail2". So we end up with WM_CLASS(STRING) = "kmail", "kmail2", as confirmed by xprop. I notice that e.g. firefox has WM_CLASS(STRING) = "Navigator", "Firefox". So the second string is the one that matters? REPOSITORY R120 Plasma Workspace REVISION DETAIL https://phabricator.kde.org/D4600 EMAIL PREFERENCES https://phabricator.kde.org/settings/panel/emailpreferences/ To: dfaure, hein Cc: plasma-devel, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas, apol
