SUMMARY Using XFCE with Plank as a dock, two Kmail icons appear in the dock when kmail is running, both labelled "KMail". One of the icons is featuring a zero in a red filled circle. STEPS TO REPRODUCE 1. Install plank (other docks might exhibit the same phenomenon) on XFCE (not sure if other desktop environments exhibit the same issue) 2. launch kmail OBSERVED RESULT two KMail icons in the dock EXPECTED RESULT only one Kmail icon in the dock SOFTWARE/OS VERSIONS Manjaro Linux with XFCE ADDITIONAL INFORMATION This might be related to the following bug report: https://bugs.kde.org/show_bug.cgi?id=359600 Also, it is conspicuous that KMail's .desktop file does not have a StartWMClass entry. Adding StartWMClass=kmail does not change things though. However I noticed when I add that line to kmail_view.desktop, still two icons appear in the dock, but one of them is now labelled "kmail view" instead of just "kmail". Are two applications (threads or whatever it is called) launched, and the desktop environment does not understand that they are in fact one single kmail instance?
Additional information: when I switch off "show unread email in taskbar" in Configure Kmail -> Appearance->System Tray, the second icon, the one with the 0 in the red solid circle, no longer shows up in the dock. Only the normal KMail icon remains. Makes me wonder why showing the number of unread emails in the taskbar results in a second icon. The 0 in the red circle is probably supposed to be the number of unread emails. However in my test setup it is a four-digit number, definitely not 0.