Hai...

i have some webapps generated by chromium. Every webapps has it's own desktop file, with a separate cache directory and a StartupWMClass.
When i use the ALT-Tab the application launcher displays the wrong icon (favicons) not the icons, that i configured in the desktop file (see the attachment).

In the cairo dock the icons are correctly displayed (also in the gnome shell).

Here is a example desktop file:

[Desktop Entry]
Comment[de]=
Comment=
Exec=chromium --user-data-dir="/home/volker/Dokumente/Linux/Chrome_data_dirs/OTRS/" --app="http://XXX.XXX.XXX.XXX/otrs/index.pl" --class=OTRS
GenericName[de]=
GenericName=
Icon=/home/volker/icons/Andere/otrs.png
MimeType=
Name[de]=OTRS
Name=OTRS
Path=
StartupNotify=true
StartupWMClass=OTRS
Terminal=false
TerminalOptions=
Type=Application
X-DBUS-ServiceName=
X-DBUS-StartupType=
X-KDE-SubstituteUID=false
X-KDE-Username=

Thank you very much.

Regards

Volker Holthaus

Reproducible: Always

Steps to Reproduce:
1. Generate chromium webapp
2. Change the desktop file (see example)
3. start the application and try to change with ALT-Tab
Actual Results:  
Display of the favicon from the website of the webapp

Expected Results:  
Display of the configured icon in the desktop file for the webapp