It is possible to install multiple desktops, but the last installed one will be used by default by startx, XRDP and VNC servers. One needs to define session details otherwise with config files. I think there is a tool as well. I’ll have a look.
Ah, this should do it:
sudo update-alternatives --config x-session-manager
Hm, this choice leaves me a bit confused… What exactly is the difference here? I mean it could be that “automatically” chosing the wrong app here could cause my faulty behaviour… And how do I get my set up “LXDE” desktop here into the choice?
Hmm, the related command is /usr/bin/startlxde. Strange that it doesn’t setup itself as session manager alternative. I’ll try to replicate when I’m home, probably there is another package which does it and otherwise it can be added manually as alternative.
EDIT: But you have LXDE installed, right? According to the Debian wiki it should then be available as alternative: LXDE - Debian Wiki
Update: I have sold my Pi2b. Before it went out I make a check on it. With a Pi 2b and the normal Raspberry Pi OS, I can fluently run any browser and application for at least 1 h. I am confused. How can I configure badly a system with a few commands so that a Pi4b 2GB works slower than a Pi 2b?? And this even I use the normal “fat” OS from Raspberry Pi and on the Pi 4b a dietpi…
@MichaIng Did you make any progress with startlxde? I want nothing special:
That’s it! That should be feasible. Now I have bought a Pi4b with 8GB (nearly double the price like my first one 1,5 years ago)…Because it looked like there is a lack of memory… But on the other hand, if a pi 2b (which is obviously slower) could relatively fluently work with all the apps without freezing (ok, I skipped the LMS, that is only running on the Pi4b)…
Any ideas, how to quickly come out of these tricky situation?
Ah, I thought running dietpi-config and choosing LXDE would be sufficient?
Do I have to install some debian packages via apt?
The “normal” use case would be to use dietpi-software and select one desktop environment. This should install all required packages.
OK I went through all software packages in dietpi-config and checked all which I intended probably to use…
So I don’t know why, but lxde was not installed according to dietpi-software. I try to again install it, but went into unmet dependencies for libgail-3-0 (requiring libgtk-3-0, which was only as rpt instead of Deb) 
ME Accessibility Implementation Library -- shared libraries
libgail18-dbgsym/stable 2.24.33-2+rpt1 arm64
(none)
root@DietPiPaeddasBKServer:/tmp/DietPi-Software# apt install libgail-3*
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'libgail-3-0-dbgsym' for glob 'libgail-3*'
Note, selecting 'libgail-3-dev' for glob 'libgail-3*'
Note, selecting 'libgail-3-doc' for glob 'libgail-3*'
Note, selecting 'libgail-3-0' for glob 'libgail-3*'
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
libgail-3-0 : Depends: libgtk-3-0 (= 3.24.24-4+deb11u2) but 3.24.24-4+rpt4+deb11u2 is to be installed
libgtk-3-dev : Depends: libgtk-3-0 (= 3.24.24-4+deb11u2) but 3.24.24-4+rpt4+deb11u2 is to be installed
E: Unable to correct problems, you have held broken packages.
root@DietPiPaeddasBKServer:/tmp/DietPi-Software# apt install libgtk-3-0*
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'libgtk-3-0-dbgsym' for glob 'libgtk-3-0*'
Note, selecting 'libgtk-3-0' for glob 'libgtk-3-0*'
0 upgraded, 0 newly installed, 0 to remove and 5 not upgraded.
root@DietPiPaeddasBKServer:/tmp/DietPi-Software# apt -f upgrade
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 5 not upgraded.
root@DietPiPaeddasBKServer:/tmp/DietPi-Software#
I have upgraded Pi4b to 8GB.
Ok, after following your instructions and tips above - Now LXDE is working fine, despite the error message above!
Speed is ok!!! Thunderbird works perfect with 3 email accounts. Tabbed Browsing is working fine!
But I can only log in as a normal user, not as root. If I log in as root, only a green display is shown (with RDP (XRDP/LXDE)):
Normal User :
root User:
Log of logfile_storage/xrdp-sesman.ini:
[20220805-12:41:12] [INFO ] ++ created session (access granted): username pwein, ip ::ffff:192.168.100.120:3469 - socket: 12
[20220805-12:41:12] [INFO ] starting Xorg session...
[20220805-12:41:12] [INFO ] Found X server running at /tmp/.X11-unix/X10
[20220805-12:41:12] [INFO ] Found X server running at /tmp/.X11-unix/X11
[20220805-12:41:12] [INFO ] Starting session: session_pid 5921, display :12.0, width 1920, height 1080, bpp 24, client ip ::ffff:192.168.100.120:3469 - socket: 12, user name pwein
[20220805-12:41:12] [INFO ] [session start] (display 12): calling auth_start_session from pid 5921
[20220805-12:41:12] [ERROR] sesman_data_in: scp_process_msg failed
[20220805-12:41:13] [ERROR] sesman_main_loop: trans_check_wait_objs failed, removing trans
[20220805-12:41:13] [INFO ] Starting X server on display 12: /usr/lib/xorg/Xorg :12 -auth .Xauthority -config xrdp/xorg.conf -noreset -nolisten tcp -logfile .xorgxrdp.%s.log
[20220805-12:41:13] [INFO ] Found X server running at /tmp/.X11-unix/X12
[20220805-12:41:13] [INFO ] Found X server running at /tmp/.X11-unix/X12
[20220805-12:41:13] [INFO ] Found X server running at /tmp/.X11-unix/X12
[20220805-12:41:13] [INFO ] Session started successfully for user pwein on display 12
[20220805-12:41:13] [INFO ] Starting the xrdp channel server for display 12
[20220805-12:41:13] [INFO ] Starting the default window manager on display 12: /etc/xrdp/startwm.sh
[20220805-12:41:13] [INFO ] Session in progress on display 12, waiting until the window manager (pid 5922) exits to end the session
[20220805-12:41:32] [INFO ] Socket 8: AF_INET6 connection received from ::1 port 57782
[20220805-12:41:34] [ERROR] pam_authenticate failed: Authentication failure
[20220805-12:41:34] [INFO ] Username or password error for user: KOSTALDE\root
[20220805-12:41:34] [ERROR] sesman_data_in: scp_process_msg failed
[20220805-12:41:34] [ERROR] sesman_main_loop: trans_check_wait_objs failed, removing trans
[20220805-12:41:46] [INFO ] Socket 8: AF_INET6 connection received from ::1 port 57784
[20220805-12:41:46] [INFO ] Terminal Server Users group is disabled, allowing authentication
[20220805-12:41:46] [INFO ] ++ created session (access granted): username root, ip ::ffff:192.168.100.120:3497 - socket: 12
[20220805-12:41:46] [INFO ] starting Xorg session...
[20220805-12:41:46] [INFO ] Found X server running at /tmp/.X11-unix/X10
[20220805-12:41:46] [INFO ] Found X server running at /tmp/.X11-unix/X11
[20220805-12:41:46] [INFO ] Starting session: session_pid 6150, display :13.0, width 1440, height 900, bpp 24, client ip ::ffff:192.168.100.120:3497 - socket: 12, user name root
[20220805-12:41:46] [INFO ] [session start] (display 13): calling auth_start_session from pid 6150
[20220805-12:41:46] [ERROR] sesman_data_in: scp_process_msg failed
[20220805-12:41:46] [ERROR] sesman_main_loop: trans_check_wait_objs failed, removing trans
[20220805-12:41:47] [INFO ] Starting X server on display 13: /usr/lib/xorg/Xorg :13 -auth .Xauthority -config xrdp/xorg.conf -noreset -nolisten tcp -logfile .xorgxrdp.%s.log
[20220805-12:41:47] [INFO ] Found X server running at /tmp/.X11-unix/X13
[20220805-12:41:47] [INFO ] Found X server running at /tmp/.X11-unix/X13
[20220805-12:41:47] [INFO ] Found X server running at /tmp/.X11-unix/X13
[20220805-12:41:47] [INFO ] Session started successfully for user root on display 13
[20220805-12:41:47] [INFO ] Starting the xrdp channel server for display 13
[20220805-12:41:47] [INFO ] Starting the default window manager on display 13: /etc/xrdp/startwm.sh
[20220805-12:41:47] [INFO ] Session in progress on display 13, waiting until the window manager (pid 6151) exits to end the session
[20220805-13:09:32] [INFO ] Socket 8: AF_INET6 connection received from ::1 port 57786
[20220805-13:09:33] [INFO ] ++ reconnected session: username root, display :13.0, session_pid 6150, ip ::ffff:192.168.100.117:51477 - socket: 12
[20220805-13:09:33] [ERROR] sesman_data_in: scp_process_msg failed
[20220805-13:09:33] [INFO ] Starting session reconnection script on display 13: /etc/xrdp/reconnectwm.sh
[20220805-13:09:33] [ERROR] sesman_main_loop: trans_check_wait_objs failed, removing trans
[20220805-13:16:34] [INFO ] Socket 8: AF_INET6 connection received from ::1 port 57788
[20220805-13:16:34] [INFO ] ++ reconnected session: username root, display :13.0, session_pid 6150, ip ::ffff:192.168.100.117:51477 - socket: 12
[20220805-13:16:34] [ERROR] sesman_data_in: scp_process_msg failed
[20220805-13:16:34] [INFO ] Starting session reconnection script on display 13: /etc/xrdp/reconnectwm.sh
[20220805-13:16:34] [ERROR] sesman_main_loop: trans_check_wait_objs failed, removing trans