x window system: added source for last troubleshooting addition

wiki/linux/systemd.md

@@ -43,7 +43,7 @@ Alternatively it can be enabled to start at every boot by running:
 sudo systemctl enable unturned
 ```
 
-### Start/Stop/Enable/Disable a service
+### Start/Stop/Enable/Disable a service and Retrieve its Logs
 
 Services can be started by running `systemctl start <service-name>`.
 They respectively can be stopped by replacing the `start`
@@ -52,6 +52,8 @@ To start the service after boot it has to be enabled.
 This works accordingly with the keyword `enable`.
 The `disable` keyword stops the service from starting automatically.
 
+Logs of the last start of the service can be found by running `systemctl status <service-name>`. 
+
 ### Retrieving the SystemD Logs
 
 SystemD logs can easily be found using the `journalctl` command.

wiki/linux/x_window_system.md

@@ -151,3 +151,36 @@ This usually means that either the [Nvidia](/wiki/nvidia.md) kernel module is no
 This can be fixed by [installing Nvidia](/wiki/linux/nvidia.md#setup).
 If this is not the problem then the [initial ramdisk](/wiki/linux/mkinitcpio.md) should be
 [regenerated](/wiki/linux/mkinitcpio.md#manually-generate-initial-ramdisk).
+
+### File Picker Doesn't Work
+
+If the file picker doesn't work in applications like [Discord](/wiki/discord.md) for example first
+check if the desktop portal is installed.
+For that search for the package `xdg-desktop-portal` or a similar named one using your
+[package manager](/wiki/linux/package_manager.md).
+If it is installed check if it starts up correctly by using the command
+`systemctl --user status xdg-desktop-portal` as described in the
+[SystemD entry](/wiki/linux/systemd.md#startstopenabledisable-a-service-and-retrieve-its-logs).
+
+A possible error is `cannot open display` as it was described and fixed by rockzombie2 and V1del in
+an [Arch Linux](/wiki/linux/arch-linux.md)
+[forum post](https://bbs.archlinux.org/viewtopic.php?id=294808).
+To fix this you can run the following commands to temporarily make the file picker work.
+
+```sh 
+systemctl --user import-environment DISPLAY XAUTHORITY
+systemctl --user restart xdg-desktop-portal
+```
+
+If that works make sure the Xorg configs are sourced for users aswell.
+It is possible that the following code block is missing in the local `.xinitrc`.
+This would create similar errors to the ones experienced.
+
+```sh
+if [ -d /etc/X11/xinit/xinitrc.d ] ; then
+    for f in /etc/X11/xinit/xinitrc.d/?*.sh ; do
+        [ -x "$f" ] && . "$f"
+    done
+    unset f
+fi
+```