Alt-tab swither doesn't recognize icons of sudh apps like: Gnome disks, gnome clocks, steam games. And it gets wrong icons of Libreoffice.
According to this report (https://bugs.documentfoundation.org/show_bug.cgi?id=65754) "This problem is in xfce enviroment too. In xfce, icons showed in alt+tab dialog are loaded from _NET_WM_ICON property. You can get this propery by "xprop -id $XID _NET_WM_ICON" and XID from xwininf app."
Other DEs read icons from some other source
Related bug in xfce-panel: https://bugzilla.xfce.org/show_bug.cgi?id=11776
The same bug on LO bugtacker https://bugs.documentfoundation.org/show_bug.cgi?id=79429
Created attachment 6149
Low res icon of document with orange stripe and green plus is Libreoffice Writer. The icon in the right (white star on red bookmark) is Wunderlist, chrome app, low res too.
You mean the icon size selected is too small? Or the icons are not themed?
No the size of some icons is right. XFWM should change the place where it gets apps' icons from (change the way of parsing). For example in compiz alt tab switcher "gnome disks" will have its icon and Libreoffice will get the right icon, with the right resolution.
In xfwm alttab switcher gnome disks doesn't have any icon at all, but gnome disks have icon in XFCE_settings, in Whisker menu. xfwm behaves different, not in the way of standarts a bit.
Gedit used to show the generic icon too. It was fixed some time ago.
The icons have to be set correctly by the application, Xfwm4 already uses the "correct" way of getting application icons (at least as far as X11 is concerned).