robert ~ # emerge -p xfce4-panel

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild     U ] xfce-base/libxfce4util-4.4.0-r1 [4.2.3.2] 
[ebuild     U ] xfce-base/libxfcegui4-4.4.0 [4.2.3] USE="-doc% -startup-notification%" 
[ebuild     U ] xfce-base/libxfce4mcs-4.4.0 [4.2.3] USE="-doc% -startup-notification%" 
[ebuild     U ] xfce-base/xfce-mcs-manager-4.4.0 [4.2.3] 
[ebuild  N    ] xfce-base/xfce4-panel-4.4.0  USE="-debug -doc -startup-notification" 
[blocks B     ] >=xfce-base/xfce4-panel-4.3 (is blocking xfce-extra/xfce4-sensors-0.7.0, xfce-extra/xfce4-xkb-0.3.5)
robert ~ # emerge --unmerge xfce4-panel

--- Couldn't find 'xfce4-panel' to unmerge.

>>> No packages selected for removal by unmerge