  The spin-flip M1 giant resonance is explored in the framework of Random Phase
Approximation on the basis of the Skyrme energy functional. A representative
set of eight Skyrme parameterizations (SkT6, SkM*, SLy6, SG2, SkO, SkO', SkI4,
and SV-bas) is used. Light and heavy, spherical and deformed nuclei ($^{48}$Ca,
$^{158}$Gd, $^{208}$Pb, and $^{238}$U) are considered. The calculations show
that spin densities play a crucial role in forming the collective shift in the
spectrum. The interplay of the collective shift and spin-orbit splitting
determines the quality of the description. None of the considered Skyrme
parameterizations is able to describe simultaneously the M1 strength
distribution in closed-shell and open-shell nuclei. It is found that the
problem lies in the relative positions of proton and neutron spin-orbit
splitting. Necessity to involve the tensor and isovector spin-orbit interaction
is called for.
