Fix Windows: run tmux setup commands individually, attach via ExecProcess

psmux on Windows doesn't handle ; separators when args are passed
individually via exec.Command. Instead of chaining commands with ;,
run each setup command (new-session, set-option, split-window, etc.)
as individual exec.Command calls. Only tmux attach uses ExecProcess
so it properly takes over the terminal.

cmd/kctl-tui/full.go

@@ -280,35 +280,40 @@ func (m *fullModel) startTmuxSession() tea.Cmd {
 	ctxA := m.cfg.ResolveContext(envA, m.selectedContext)
 	k9sCmdA := fmt.Sprintf("k9s --context %s -n %s", ctxA, m.selectedNamespace)
 
-	// Kill stale session first (ignore error if none exists).
-	killErr := exec.Command("tmux", "kill-session", "-t", "kctl").Run()
 	fmt.Fprintf(os.Stderr, "[debug] selfPath=%s\n", selfPath)
 	fmt.Fprintf(os.Stderr, "[debug] panelCmd=%s\n", panelCmd)
-	fmt.Fprintf(os.Stderr, "[debug] kill-session err=%v\n", killErr)
 
-	args := []string{
+	// Kill stale session first (ignore error if none exists).
-		"new-session", "-d", "-s", "kctl",
+	exec.Command("tmux", "kill-session", "-t", "kctl").Run()
-		panelCmd, ";",
+
-		"set-option", "-t", "kctl", "remain-on-exit", "on", ";",
+	// Run setup commands individually — this avoids the ; separator
-		"split-window", "-v", "-t", "kctl:0.0", k9sCmdA, ";",
+	// issue on Windows where psmux doesn't handle chained args.
+	setup := [][]string{
+		{"new-session", "-d", "-s", "kctl", panelCmd},
+		{"set-option", "-t", "kctl", "remain-on-exit", "on"},
+		{"split-window", "-v", "-t", "kctl:0.0", k9sCmdA},
 	}
 	if len(m.cfg.Envs) > 1 {
 		envB := m.cfg.Envs[1]
 		ctxB := m.cfg.ResolveContext(envB, m.selectedContext)
 		k9sCmdB := fmt.Sprintf("k9s --context %s -n %s", ctxB, m.selectedNamespace)
-		args = append(args,
+		setup = append(setup, []string{"split-window", "-v", "-t", "kctl:0.1", k9sCmdB})
-			"split-window", "-v", "-t", "kctl:0.1", k9sCmdB, ";",
-		)
 	}
-	args = append(args,
+	setup = append(setup,
-		"select-layout", "-t", "kctl", "even-vertical", ";",
+		[]string{"select-layout", "-t", "kctl", "even-vertical"},
-		"select-pane", "-t", "kctl:0.0", ";",
+		[]string{"select-pane", "-t", "kctl:0.0"},
-		"attach", "-t", "kctl",
 	)
 
-	fmt.Fprintf(os.Stderr, "[debug] tmux args: %v\n", args)
+	for _, args := range setup {
-	c := exec.Command("tmux", args...)
+		if out, err := exec.Command("tmux", args...).CombinedOutput(); err != nil {
+			fmt.Fprintf(os.Stderr, "[debug] tmux %s failed: %v\n%s\n", args[0], err, out)
+			return func() tea.Msg { return tmuxDoneMsg{err: fmt.Errorf("tmux %s: %w", args[0], err)} }
+		}
+	}
 
+	// Only attach uses tea.ExecProcess so it takes over the terminal.
+	fmt.Fprintf(os.Stderr, "[debug] tmux attach -t kctl\n")
+	c := exec.Command("tmux", "attach", "-t", "kctl")
 	return tea.ExecProcess(c, func(err error) tea.Msg {
 		return tmuxDoneMsg{err: err}
 	})