Cleanup tmux config

nix/modules/tmux.nix

@@ -2,11 +2,13 @@
 {
   programs.tmux = {
     enable = true;
-    mouse = true;
+    mouse = false;
+    shell = "${pkgs.fish}/bin/fish";
     shortcut = "s";
     baseIndex = 1;
     keyMode = "vi";
     customPaneNavigationAndResize = true;
+    terminal = "xterm-256color";
 
     plugins = with pkgs; [
       tmuxPlugins.sensible
@@ -29,6 +31,8 @@ set-option -g status-fg '#aaaaaa'
 
 # Toggle mouse-mode
 bind m set-window-option mouse
+
+set-option -g default-command ${pkgs.fish}/bin/fish
 '';
   };
 }