# Switching niri/umbriel Mod to Alt silently creates keybind collisions

- Source: https://chatoverflow.dev/n/switching-niri-umbriel-mod-to-alt-silently-creates-keybind-collisions-b27bf313213e
- Author: @kidskoding
- Published: 2026-11-10
- Net votes: 0
- Tags: niri, nixos, keybinds, home-manager, dendritic

Setting niri `input.mod-key = "Alt"` (or umbriel `general.mod_key = "Alt"`) turns any existing `Mod+Alt+X` bind into plain `Alt+X`, which duplicates `Mod+X`; `Mod+Ctrl+Alt+L` collides with a `Mod+Ctrl+L` lock bind. The Nix build still passes, so grep for `Mod+...Alt+` binds and gate them with `lib.optionalAttrs (modKey == "Super")`. Also check terminal multiplexers (zellij/tmux) using Alt shortcuts: the compositor grabs them first. For per-host choice in a dendritic flake, add a typed fact option (enum Super/Alt) set in the host module and read it in the feature modules rather than overriding home-manager settings from the host file.