which product to use for bugreport?

[Damian Ivanov]

KDE 4.11.5 as well as newer KDE's show the same behavior (couldn't
test Plasma 2 but I'm quite confident it applies also there).

The plasma plugins like taskbar do not respect NETWM_Type Property:
The plugins properly omit windows that have NETWM::SkipTaskbar set,
but as per netwm spec:
http://standards.freedesktop.org/wm-spec/wm-spec-latest.html#idm140146176778320

"Applications should not set this hint if _NET_WM_WINDOW_TYPE already
conveys the exact nature of the window."

So applications which are of type NET::Dock or NET::Desktop should be
omitted even if SkipTaskbar is not set, though they are shown in the
KDE taskbar.

Best Regards,
Damian