PS:
Und als “Beweis” dass das kein Plasma-spezifisches Problem ist, hier ein Bildschirmfoto von IceWM (Leap 42.3): 
http://susepaste.org/images/95702273.png
$ xprop
_NET_WM_USER_TIME_WINDOW(WINDOW): window id # 0x2a00056
_ICEWM_TRAY(CARDINAL) = 0
_WIN_LAYER(CARDINAL) = 4
_NET_WM_DESKTOP(CARDINAL) = 0
_WIN_WORKSPACE(CARDINAL) = 0
WM_STATE(WM_STATE):
window state: Normal
icon window: 0x0
_NET_WM_STATE(ATOM) =
_WIN_STATE(CARDINAL) = 0, 1023
_NET_FRAME_EXTENTS(CARDINAL) = 2, 2, 19, 2
_NET_WM_ALLOWED_ACTIONS(ATOM) = _NET_WM_ACTION_MOVE, _NET_WM_ACTION_RESIZE, _NET_WM_ACTION_CLOSE, _NET_WM_ACTION_MINIMIZE, _NET_WM_ACTION_MAXIMIZE_HORZ, _NET_WM_ACTION_MAXIMIZE_VERT, _NET_WM_ACTION_SHADE, _NET_WM_ACTION_ABOVE, _NET_WM_ACTION_BELOW, _NET_WM_ACTION_STICK, _NET_WM_ACTION_CHANGE_DESKTOP
_NET_WM_VISIBLE_ICON_NAME(UTF8_STRING) =
_NET_WM_VISIBLE_NAME(UTF8_STRING) = "YaST2"
_NET_WM_ICON_NAME(UTF8_STRING) =
XdndAware(ATOM) = BITMAP
WM_NAME(STRING) = "YaST2"
_NET_WM_NAME(UTF8_STRING) = "YaST2"
Zum Vergleich das “YaST-Kontrollzentrum” Fenster (mit Icon):
$ xprop
_NET_WM_USER_TIME_WINDOW(WINDOW): window id # 0x2800013
_ICEWM_TRAY(CARDINAL) = 0
_WIN_LAYER(CARDINAL) = 4
_NET_WM_DESKTOP(CARDINAL) = 0
_WIN_WORKSPACE(CARDINAL) = 0
WM_STATE(WM_STATE):
window state: Normal
icon window: 0x0
_NET_WM_STATE(ATOM) =
_WIN_STATE(CARDINAL) = 0, 1023
_NET_FRAME_EXTENTS(CARDINAL) = 2, 2, 19, 2
_NET_WM_ALLOWED_ACTIONS(ATOM) = _NET_WM_ACTION_MOVE, _NET_WM_ACTION_RESIZE, _NET_WM_ACTION_CLOSE, _NET_WM_ACTION_MINIMIZE, _NET_WM_ACTION_MAXIMIZE_HORZ, _NET_WM_ACTION_MAXIMIZE_VERT, _NET_WM_ACTION_SHADE, _NET_WM_ACTION_ABOVE, _NET_WM_ACTION_BELOW, _NET_WM_ACTION_STICK, _NET_WM_ACTION_CHANGE_DESKTOP
_NET_WM_VISIBLE_ICON_NAME(UTF8_STRING) =
_NET_WM_VISIBLE_NAME(UTF8_STRING) = "YaST-Kontrollzentrum @ amiga"
_NET_WM_ICON(CARDINAL) = Icon (48 x 48):
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_NET_WM_ICON_NAME(UTF8_STRING) =
XdndAware(ATOM) = BITMAP
WM_NAME(STRING) = "YaST-Kontrollzentrum @ amiga"
_NET_WM_NAME(UTF8_STRING) = "YaST-Kontrollzentrum @ amiga"
_MOTIF_WM_HINTS(_MOTIF_WM_HINTS) = 0x3, 0x3e, 0x7e, 0x0, 0x0
_NET_WM_WINDOW_TYPE(ATOM) = _NET_WM_WINDOW_TYPE_NORMAL
_XEMBED_INFO(_XEMBED_INFO) = 0x0, 0x1
WM_CLIENT_LEADER(WINDOW): window id # 0x2800007
WM_HINTS(WM_HINTS):
Client accepts input or input focus: True
Initial state is Normal State.
_NET_WM_PID(CARDINAL) = 2876
_NET_WM_SYNC_REQUEST_COUNTER(CARDINAL) = 41943046
WM_CLASS(STRING) = "y2controlcenter", "y2controlcenter"
WM_PROTOCOLS(ATOM): protocols WM_DELETE_WINDOW, WM_TAKE_FOCUS, _NET_WM_PING, _NET_WM_SYNC_REQUEST
WM_NORMAL_HINTS(WM_SIZE_HINTS):
user specified location: 138, 530
user specified size: 680 by 420
program specified minimum size: 182 by 157
window gravity: NorthWest
Der Unterschied dürfte klar sein…