diff --git a/.tmux b/.tmux
index c27c952fa..ca108368a 100755
--- a/.tmux
+++ b/.tmux
@@ -7,13 +7,13 @@ session_name="${1:-oliverdavies-uk}"
 session_path="${2:-$(pwd)}"
 
 if tmux has-session -t="${session_name}" 2> /dev/null; then
-  tmux attach -t "${session_name}"
-  exit
+  tmux attach -t "${session_name}" ||
+    tmux switch-client -t "${session_name}"
 fi
 
 tmux new-session -d -s "${session_name}" -n vim -c "${session_path}"
 
-# 1. Main window: Vim
+# 1. Main window: Vim.
 tmux send-keys -t "${session_name}:vim" "nvim" Enter
 tmux split-pane -t "${session_name}:vim" -h -c "${session_path}" -p 40
 tmux send-keys -t "${session_name}:vim.right" "./run start" Enter
@@ -23,3 +23,5 @@ tmux new-window -t "${session_name}" -c "${session_path}"
 
 tmux switch-client -t "${session_name}:vim.left" ||
   tmux attach -t "${session_name}:vim.left"
+
+# vim: ft=bash
diff --git a/build.yaml b/build.yaml
index d692da441..cfc8d9d84 100644
--- a/build.yaml
+++ b/build.yaml
@@ -14,3 +14,6 @@ git:
   ignore:
     - /node_modules/
     - /source/build/
+
+experimental:
+  createTmuxStartupFile: true