New feature java.awt.Taskbar is declared in JDK9 as supported on Linux for Unity only. A call to Taskbar.isTaskbarSupported() query on Gnome 3 reports false.

However start it on Xfce4 from Ubuntu 14.04, and Taskbar is reported as supported with Menu, Progress value, and User Attention. That is misleading.

Note that in my case it is Xfce4 installed as an option side-by-side with Unity (not from Xubuntu distribution).

Does sniffer look for an installed library or something?