I added filter_mode_shell_up_key_binding = “directory” to me ~/.config/atuin/config.toml but see now difference.
How can i determine why this config is not being applied?
Hello and welcome. How does your config look like? Is the filter mode maybe added to a wrong table (i.e, inside [sync], for example). filter_mode_shell_up_key_binding should not be in any table, meaning it should be defined before any table is named. Furthermore, did you try restarting your shell (it should not be necessary, but just in case)? What does your echo $ATUIN_CONFIG_DIR give?
Also, could you provide the output of the command atuin doctor?
moving the setting to the top of the config worked.
Thanks so much!
Where can I learn more about tables in Atuin configs?
Tables, or dictionaries, are a TOML construct. Atuin uses them to separate options. You can learn more about the Atuin options in the official Atuin documentation. When an option is to be set inside a specific table, it is always specified in the documentation. Have fun with Atuin 
You can also set my previous answer as solution so this topic appears as resolved 