Xtart or Fluxbox should be patched. Where does Mandrake gets its /etc/X11/wmsession.d/XX from. If it is Debian what is their policy. If there is no policy then i would suggest: pick a number between 17 & 98 for your windowmanager and check if it is not taken.
ps for i forget shouldn't /usr/bin/Xtart be /usr/X11R6/bin/Xtart ps1 suggest 99 to be twm
