hein added a comment.
I went through it multiple times with different KMail people and they promised to fix it but somehow it doesn't happen ... I think it's inertia from some sort of legacy compat hell they locked themselves into. If memory serves me right their .desktop file is kmail.desktop but their Qt product/component name is kmail2, which is what WM_CLASS for the main window gets derived from ultimately. One of them needs to be changed for things to match up. REPOSITORY R120 Plasma Workspace BRANCH Plasma/5.9 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