diff --git a/sesman/startwm.sh b/sesman/startwm.sh
index fd0535ca72..7c39f24cbf 100755
--- a/sesman/startwm.sh
+++ b/sesman/startwm.sh
@@ -57,15 +57,18 @@ post_start()
 
 get_xdg_session_startupcmd()
 {
-  # DESKTOP_SESSION should be set in sesman.ini in the SessionVariables section.
-  # If set and valid then the STARTUP command will be taken from there
+  # If DESKTOP_SESSION is set and valid then the STARTUP command will be taken from there
+  # GDM exports environment variables XDG_CURRENT_DESKTOP and XDG_SESSION_DESKTOP.
+  # This follows it.
   if [ -n "$1" ] && [ -d /usr/share/xsessions ] \
     && [ -f "/usr/share/xsessions/$1.desktop" ]; then
     STARTUP=$(grep ^Exec= "/usr/share/xsessions/$1.desktop")
     STARTUP=${STARTUP#Exec=*}
     XDG_CURRENT_DESKTOP=$(grep ^DesktopNames= "/usr/share/xsessions/$1.desktop")
     XDG_CURRENT_DESKTOP=${XDG_CURRENT_DESKTOP#DesktopNames=*}
-    echo "env XDG_CURRENT_DESKTOP=\"$XDG_CURRENT_DESKTOP\" $STARTUP"
+    XDG_CURRENT_DESKTOP=${XDG_CURRENT_DESKTOP//;/:}
+    export XDG_CURRENT_DESKTOP
+    export XDG_SESSION_DESKTOP="$DESKTOP_SESSION"
   fi
 }
 
@@ -80,15 +83,24 @@ wm_start()
   # debian
   if [ -r /etc/X11/Xsession ]; then
     pre_start
-    
+
+    # if you want to start preferred desktop environment,
+    # add following line,
+    #  [ -n "$XRDP_SESSION" ] && export DESKTOP_SESSION=<your preferred desktop>
+    # in either of following file.
+    # 1. ~/.profile
+    # 2. create a file (any_filename.sh is OK) in /etc/profile.d
+    # <your preferred desktop> shall be one of "ls -1 /usr/share/xsessions/|cut -d. -f1"
+    # e.g.  [ -n "$XRDP_SESSION" ] && export DESKTOP_SESSION=ubuntu
+
     # STARTUP is the default startup command.
     # if $1 is empty and STARTUP was not set
     # /etc/X11/Xsession.d/50x11-common_determine-startup will fallback to
     # x-session-manager
     if [ -z "$STARTUP" ] && [ -n "$DESKTOP_SESSION" ]; then
-      STARTUP="$(get_xdg_session_startupcmd "$DESKTOP_SESSION")"
+      get_xdg_session_startupcmd "$DESKTOP_SESSION"
     fi
-    
+
     . /etc/X11/Xsession
     post_start
     exit 0