Comment # 3 on bug 1171415 from Dirk Weber

Thanks for finding this workaround, for me this was a bug blocking the upgrade
to Leap 15.2.

Just some additional remarks:

For Leap 15.2 in xrdp-0.9.13-lp152.2.2 the script 
/etc/xrdp/startwm.sh
in the function 
wm_start()
hard codes the SESSION
SESSION="gnome"
and after this has a pointless case statement (pointless because the SESSION at
this point is always gnome):

case $SESSION in
    sle)
...
      ;;
    gnome)
...
      ;;
    icewm)
...
      ;;
  esac

I do not have gnome installed and an xrdp session can not be established
probably because no desktop can be started.

If I modify the 
/etc/xrdp/startwm.sh
in the function 
wm_start()
and change the SESSION to icewem - which is installed
SESSION="icewm"
the xrdp connection can be started and I get a functional desktop with icewm.

The script startwm.sh in the function 
pre_start()
sources some user configuration files (~/.bash_profile, ~/.bash_login,
~/.profile). A solution would be that if SESSION is set in one of them that
this value is not overwritten in start_wm().

In Leap 15.1 if have a file ~/.xsession to select the desktop to be started by
the xrdp session.