i have "awlays visible" option enabled in xmms options
and no special options for xmms in icewm's winoptions.
if i start xmms it doesn't stay on top, but if I do C-A
C-A (disbale "on top" option and re-enable it) xmms
starts to behave as expected.
this is with icewm 1.2.14 and xmms 1.2.10.
Also "Show on all desktops" xmms option is ignored, it
is visible only on original desktop.
I guess it may be because some window hints get ignored
on window's initial mapping.