diff --git a/backend/00-router.go b/backend/00-router.go
index 2492605..5842898 100644
--- a/backend/00-router.go
+++ b/backend/00-router.go
@@ -20,6 +20,7 @@ func RegisterRoutes(mux *http.ServeMux) {
 	// Viewer (lokale mbox betrachten + weiterleiten)
 	mux.HandleFunc("/view", viewerHandler)
 	mux.HandleFunc("/view/message", messageHandler)
+	mux.HandleFunc("/view/target", targetMessageHandler)
 	mux.HandleFunc("/view/forward", forwardHandler)
 }
 
diff --git a/backend/08-viewer.go b/backend/08-viewer.go
index f8cea4e..82914a5 100644
--- a/backend/08-viewer.go
+++ b/backend/08-viewer.go
@@ -35,6 +35,7 @@ func viewerHandler(w http.ResponseWriter, r *http.Request) {
 func messageHandler(w http.ResponseWriter, r *http.Request) {
 	account := r.URL.Query().Get("account")
 	folder := r.URL.Query().Get("folder")
+	targetAccount := r.URL.Query().Get("target_account")
 	index, err := strconv.Atoi(r.URL.Query().Get("index"))
 	if err != nil {
 		http.Error(w, "bad index", http.StatusBadRequest)
@@ -52,10 +53,10 @@ func messageHandler(w http.ResponseWriter, r *http.Request) {
 	}
 	msg, err := mail.ReadMessage(bytes.NewReader(raw))
 	if err != nil {
-		renderReadPanePair(w, account, folder, index, raw, "(unlesbar)", "", "", string(raw))
+		renderReadPanePair(w, account, folder, targetAccount, index, raw, "(unlesbar)", "", "", string(raw))
 		return
 	}
-	renderReadPanePair(w, account, folder, index, raw,
+	renderReadPanePair(w, account, folder, targetAccount, index, raw,
 		decodeHeader(msg.Header.Get("Subject")),
 		decodeHeader(msg.Header.Get("From")),
 		decodeHeader(msg.Header.Get("Date")),
@@ -63,6 +64,29 @@ func messageHandler(w http.ResponseWriter, r *http.Request) {
 	)
 }
 
+func targetMessageHandler(w http.ResponseWriter, r *http.Request) {
+	account := r.URL.Query().Get("account")
+	folder := r.URL.Query().Get("folder")
+	targetAccount := r.URL.Query().Get("target_account")
+	index, err := strconv.Atoi(r.URL.Query().Get("index"))
+	if err != nil {
+		http.Error(w, "bad index", http.StatusBadRequest)
+		return
+	}
+	path, err := mboxPath(account, folder)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	raw, err := ReadMboxMessage(path, index)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusNotFound)
+		return
+	}
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	fmt.Fprint(w, renderTargetPane(account, folder, targetAccount, index, raw))
+}
+
 func forwardHandler(w http.ResponseWriter, r *http.Request) {
 	// TODO Codex: GET = Weiterleiten-Formular (An/Betreff/Text), POST =
 	// ForwardMessage() aufrufen. NUR hier kommt SMTP zum Einsatz -- der Umzug
@@ -71,7 +95,7 @@ func forwardHandler(w http.ResponseWriter, r *http.Request) {
 
 func renderViewerTree(w http.ResponseWriter) {
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
-	fmt.Fprint(w, `<div class="pane-head">Backups</div>`)
+	fmt.Fprint(w, `<div class="pane-head">Originale</div>`)
 	entries, err := os.ReadDir(Cfg.MboxRoot)
 	if err != nil {
 		fmt.Fprintf(w, `<div class="ef-empty">%s</div>`, html.EscapeString(err.Error()))
@@ -88,7 +112,7 @@ func renderViewerTree(w http.ResponseWriter) {
 			continue
 		}
 		found = true
-		fmt.Fprintf(w, `<div class="tree-node account">%s</div>`, html.EscapeString(account))
+		fmt.Fprintf(w, `<div class="tree-node account">%s</div>`, html.EscapeString(sourceAccountLabel(account)))
 		for _, path := range mboxes {
 			folder := strings.TrimSuffix(filepath.Base(path), ".mbox")
 			fmt.Fprintf(w, `<a class="tree-node" href="/view?account=%s&amp;folder=%s" hx-get="/view?account=%s&amp;folder=%s" hx-target="#list" hx-swap="innerHTML">%s</a>`,
@@ -132,7 +156,7 @@ func renderMessageList(w http.ResponseWriter, account, folder, q string) {
 		if from == "" {
 			from = "(ohne Absender)"
 		}
-		fmt.Fprintf(w, `<a class="msg-row" href="/view/message?account=%s&amp;folder=%s&amp;index=%d" hx-get="/view/message?account=%s&amp;folder=%s&amp;index=%d" hx-target="#read" hx-swap="innerHTML"><span class="msg-from">%s</span><span class="msg-subject">%s</span><span class="msg-date">%s</span></a>`,
+		fmt.Fprintf(w, `<a class="msg-row" href="/view/message?account=%s&amp;folder=%s&amp;index=%d" hx-get="/view/message?account=%s&amp;folder=%s&amp;index=%d" hx-include="#target-account-select" hx-target="#read" hx-swap="innerHTML"><span class="msg-from">%s</span><span class="msg-subject">%s</span><span class="msg-date">%s</span></a>`,
 			urlEsc(account), urlEsc(folder), entry.Index, urlEsc(account), urlEsc(folder), entry.Index,
 			html.EscapeString(from), html.EscapeString(subject), html.EscapeString(entry.Date))
 	}
@@ -143,10 +167,10 @@ func renderMessageList(w http.ResponseWriter, account, folder, q string) {
 	}
 }
 
-func renderReadPanePair(w http.ResponseWriter, account, folder string, index int, raw []byte, subject, from, date, body string) {
+func renderReadPanePair(w http.ResponseWriter, account, folder, targetAccount string, index int, raw []byte, subject, from, date, body string) {
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
 	renderReadPane(w, "Original", subject, from, date, body)
-	targetHTML := renderTargetPane(account, folder, index, raw)
+	targetHTML := renderTargetPane(account, folder, targetAccount, index, raw)
 	fmt.Fprintf(w, `<div id="read-target" hx-swap-oob="innerHTML">%s</div>`, targetHTML)
 }
 
@@ -158,31 +182,40 @@ func renderReadPane(w io.Writer, title, subject, from, date, body string) {
 		html.EscapeString(title), html.EscapeString(subject), html.EscapeString(from), html.EscapeString(date), html.EscapeString(body))
 }
 
-func renderTargetPane(account, folder string, index int, raw []byte) string {
-	match, ok := findForwardedCopy(account, folder, index, raw)
+func renderTargetPane(account, folder, targetAccount string, index int, raw []byte) string {
+	var b strings.Builder
+	b.WriteString(renderTargetAccountSelect(account, folder, targetAccount, index))
+	match, ok := findForwardedCopy(account, targetAccount, raw)
 	if !ok {
 		id := messageIDHeader(raw)
 		if id == "" {
 			id = "(ohne Message-ID)"
 		}
-		return fmt.Sprintf(`<div class="pane-head">Zielkopie</div><div class="ef-empty">Keine lokale Zielkopie gefunden.<br><br>Message-ID: %s</div>`, html.EscapeString(id))
+		fmt.Fprintf(&b, `<div class="ef-empty">Keine lokale Zielkopie gefunden.<br><br>Message-ID: %s</div>`, html.EscapeString(id))
+		return b.String()
 	}
 	msg, err := mail.ReadMessage(bytes.NewReader(match.Raw))
 	if err != nil {
-		var b strings.Builder
-		renderReadPane(&b, "Zielkopie", "(unlesbar)", match.Location(), "", string(match.Raw))
+		renderReadContent(&b, "(unlesbar)", match.Location(), "", string(match.Raw))
 		return b.String()
 	}
-	var b strings.Builder
-	renderReadPane(&b, "Zielkopie: "+match.Location(),
+	renderReadContent(&b,
 		decodeHeader(msg.Header.Get("Subject")),
 		decodeHeader(msg.Header.Get("From")),
-		decodeHeader(msg.Header.Get("Date")),
+		decodeHeader(msg.Header.Get("Date"))+" | "+match.Location(),
 		messageBody(match.Raw),
 	)
 	return b.String()
 }
 
+func renderReadContent(w io.Writer, subject, from, date, body string) {
+	if subject == "" {
+		subject = "(ohne Betreff)"
+	}
+	fmt.Fprintf(w, `<div class="read-body"><div class="read-head"><h1 class="read-subject">%s</h1><div class="read-meta">Von: %s<br>Datum: %s</div></div><pre class="read-pre">%s</pre></div>`,
+		html.EscapeString(subject), html.EscapeString(from), html.EscapeString(date), html.EscapeString(body))
+}
+
 func mboxPath(account, folder string) (string, error) {
 	if account == "" || folder == "" || strings.Contains(account, "..") || strings.Contains(folder, "..") {
 		return "", fmt.Errorf("ungueltiges Postfach")
@@ -238,7 +271,7 @@ func (m forwardedMatch) Location() string {
 	return fmt.Sprintf("%s / %s #%d", m.Account, m.Folder, m.Index)
 }
 
-func findForwardedCopy(account, folder string, index int, raw []byte) (forwardedMatch, bool) {
+func findForwardedCopy(account, targetAccount string, raw []byte) (forwardedMatch, bool) {
 	id := messageIDHeader(raw)
 	if id == "" {
 		return forwardedMatch{}, false
@@ -251,6 +284,9 @@ func findForwardedCopy(account, folder string, index int, raw []byte) (forwarded
 		if !entry.IsDir() || entry.Name() == account {
 			continue
 		}
+		if targetAccount != "" && entry.Name() != targetAccount {
+			continue
+		}
 		mboxes, _ := filepath.Glob(filepath.Join(Cfg.MboxRoot, entry.Name(), "*.mbox"))
 		for _, path := range mboxes {
 			msgs, err := ReadMboxList(path)
@@ -283,3 +319,100 @@ func messageIDHeader(raw []byte) string {
 	}
 	return strings.TrimSpace(msg.Header.Get("Message-ID"))
 }
+
+func renderTargetAccountSelect(account, folder, selected string, index int) string {
+	accounts := viewerAccounts()
+	if selected == account {
+		selected = ""
+	}
+	var b strings.Builder
+	fmt.Fprintf(&b, `<div class="pane-head target-head"><span>Zielkopie</span><form class="target-select-form" hx-get="/view/target" hx-target="#read-target" hx-swap="innerHTML" hx-trigger="change from:#target-account-select">
+<input type="hidden" name="account" value="%s">
+<input type="hidden" name="folder" value="%s">
+<input type="hidden" name="index" value="%d">
+<select id="target-account-select" name="target_account" class="target-select">
+<option value="">Automatisch</option>`, html.EscapeString(account), html.EscapeString(folder), index)
+	for _, a := range accounts {
+		if a.Name == account {
+			continue
+		}
+		attr := ""
+		if a.Name == selected {
+			attr = ` selected`
+		}
+		fmt.Fprintf(&b, `<option value="%s"%s>%s</option>`, html.EscapeString(a.Name), attr, html.EscapeString(a.TargetLabel))
+	}
+	b.WriteString(`</select></form></div>`)
+	return b.String()
+}
+
+type viewerAccount struct {
+	Name        string
+	SourceLabel string
+	TargetLabel string
+}
+
+func viewerAccounts() []viewerAccount {
+	labels := accountLabels()
+	entries, err := os.ReadDir(Cfg.MboxRoot)
+	if err != nil {
+		return nil
+	}
+	var out []viewerAccount
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+		mboxes, _ := filepath.Glob(filepath.Join(Cfg.MboxRoot, entry.Name(), "*.mbox"))
+		if len(mboxes) == 0 {
+			continue
+		}
+		a := labels[entry.Name()]
+		if a.Name == "" {
+			a = viewerAccount{Name: entry.Name(), SourceLabel: entry.Name(), TargetLabel: entry.Name()}
+		}
+		out = append(out, a)
+	}
+	return out
+}
+
+func sourceAccountLabel(mboxDir string) string {
+	if a := accountLabels()[mboxDir]; a.SourceLabel != "" {
+		return a.SourceLabel
+	}
+	return mboxDir
+}
+
+func accountLabels() map[string]viewerAccount {
+	out := map[string]viewerAccount{}
+	if DB == nil {
+		return out
+	}
+	accounts, err := ListAccounts()
+	if err != nil {
+		return out
+	}
+	for _, a := range accounts {
+		dir := accountMboxDir(a)
+		source := a.SrcUser
+		if source == "" {
+			source = a.Name
+		}
+		target := a.DstUser
+		if target == "" {
+			target = a.Name
+		}
+		if a.Name != "" {
+			target = target + " (" + a.Name + ")"
+		}
+		out[dir] = viewerAccount{Name: dir, SourceLabel: source, TargetLabel: target}
+	}
+	return out
+}
+
+func accountMboxDir(a Account) string {
+	if strings.TrimSpace(a.MboxDir) != "" {
+		return a.MboxDir
+	}
+	return a.Name
+}
diff --git a/frontend-js/dist/style.css b/frontend-js/dist/style.css
index a8a6ced..78f90ba 100644
--- a/frontend-js/dist/style.css
+++ b/frontend-js/dist/style.css
@@ -73,6 +73,20 @@ body.ol2013 {
   font-weight: 600; color: var(--ol-muted);
   text-transform: none;
 }
+.target-head {
+  display: grid;
+  grid-template-columns: auto minmax(0, 1fr);
+  align-items: center;
+  gap: 10px;
+}
+.target-select-form { margin: 0; min-width: 0; }
+.target-select {
+  width: 100%;
+  height: 24px;
+  padding: 2px 6px;
+  color: var(--ol-text);
+  background: #fff;
+}
 
 .searchbar {
   position: sticky; top: 30px; z-index: 2;