Phone: swipe right to delete, Mailbox display with the dividing lines

On a phone, a conversation dragged to the right shows a red bin behind it;
let go past a third of the row and it goes to Trash, short of that it
springs back. Vertical drags still scroll (touch-action: pan-y), and a swipe
never opens the conversation. "Moved to Trash · Undo" shows for 5 s and the
move is made only after that, like Undo send — so Undo just shows the row
again; leaving the page still deletes. Not in Trash (it would be for good)
and not offline.

The ⋯ menu on a phone gains Mailbox display, holding only "Show a dividing
line between rows" (a phone has no layouts to choose).

The corner toast takes an optional action (label + run) and duration.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/components/Toast.tsx

@@ -1,32 +1,44 @@
-import { useEffect, useState } from "react";
+import { useEffect, useRef, useState } from "react";
 
-// A short confirmation in the corner — the Undo-send toast's look, without the
-// button. Raised by anything (core or a plugin bundle) with
+// A short confirmation in the corner — the Undo-send toast's look. Raised by
+// anything (core or a plugin bundle) with
 //   window.dispatchEvent(new CustomEvent("webmail:toast", { detail: { text } }))
-// e.g. "Reply sent" after answering an invitation. Gone after a few seconds.
+// e.g. "Reply sent" after answering an invitation, optionally with one action
+// (`action: { label, run }`, e.g. Undo) and its own duration (`ms`).
 const SHOW_MS = 3500;
 
+interface ToastDetail {
+  text?: string;
+  ms?: number;
+  action?: { label: string; run: () => void };
+}
+
 export function Toast({ mobile }: { mobile: boolean }) {
-  const [toast, setToast] = useState<{ text: string; seq: number } | null>(null);
+  const [toast, setToast] = useState<(ToastDetail & { seq: number }) | null>(null);
+  const timer = useRef<number | undefined>(undefined);
 
   useEffect(() => {
-    let timer: number | undefined;
     let seq = 0;
     const onToast = (e: Event) => {
-      const text = (e as CustomEvent<{ text?: string }>).detail?.text;
-      if (!text) return;
-      setToast({ text, seq: ++seq });
-      window.clearTimeout(timer);
-      timer = window.setTimeout(() => setToast(null), SHOW_MS);
+      const detail = (e as CustomEvent<ToastDetail>).detail;
+      if (!detail?.text) return;
+      setToast({ ...detail, seq: ++seq });
+      window.clearTimeout(timer.current);
+      timer.current = window.setTimeout(() => setToast(null), detail.ms ?? SHOW_MS);
     };
     window.addEventListener("webmail:toast", onToast);
     return () => {
       window.removeEventListener("webmail:toast", onToast);
-      window.clearTimeout(timer);
+      window.clearTimeout(timer.current);
     };
   }, []);
 
   if (!toast) return null;
+  const act = () => {
+    window.clearTimeout(timer.current);
+    setToast(null);
+    toast.action?.run();
+  };
   return (
     <div
       key={toast.seq}
@@ -34,11 +46,16 @@ export function Toast({ mobile }: { mobile: boolean }) {
       className={
         mobile
           ? // Level with the Compose button on the other side of the screen.
-            "fixed bottom-[calc(4.375rem+env(safe-area-inset-bottom))] left-4 z-40 flex h-11 items-center rounded-xl bg-app-fg px-4 text-[15px] font-medium text-app-surface shadow-lg"
-          : "fixed bottom-4 right-4 z-50 flex w-80 items-center rounded-lg bg-app-fg px-4 py-2.5 text-sm text-app-surface shadow-lg"
+            "fixed bottom-[calc(4.375rem+env(safe-area-inset-bottom))] left-4 z-40 flex h-11 items-center gap-4 rounded-xl bg-app-fg px-4 text-[15px] font-medium text-app-surface shadow-lg"
+          : "fixed bottom-4 right-4 z-50 flex w-80 items-center justify-between rounded-lg bg-app-fg px-4 py-2.5 text-sm text-app-surface shadow-lg"
       }
     >
-      {toast.text}
+      <span>{toast.text}</span>
+      {toast.action && (
+        <button type="button" className="font-medium text-app-accent hover:underline" onClick={act}>
+          {toast.action.label}
+        </button>
+      )}
     </div>
   );
 }

frontend/src/components/list/MessageList.tsx

@@ -1,6 +1,6 @@
 import { keepPreviousData, useQuery } from "@tanstack/react-query";
 import { useVirtualizer } from "@tanstack/react-virtual";
-import { useEffect, useRef } from "react";
+import { useEffect, useRef, useState } from "react";
 
 import { useT } from "../../i18n";
 import { api } from "../../lib/api";
@@ -96,6 +96,7 @@ export function MessageList({
   dimmedIds,
   onToggleCheck,
   compact = false,
+  onSwipeDelete,
 }: {
   threads: ThreadSummary[];
   /** Which page of the list this is. Changing it scrolls back to the top. */
@@ -113,9 +114,12 @@ export function MessageList({
   onToggleCheck: (id: string) => void;
   /** Phone layout: sender, subject and snippet stacked; no hover-only actions. */
   compact?: boolean;
+  /** Phone: swiping a row to the right deletes it (absent: no swipe). */
+  onSwipeDelete?: (id: string) => void;
 }) {
   const t = useT();
   const parentRef = useRef<HTMLDivElement>(null);
+  const swipe = useSwipeToDelete(onSwipeDelete);
   // In Trash/Spam/Archive the middle action restores; elsewhere it archives.
   const isRemovalFolder = folder === "trash" || folder === "junk" || folder === "archive";
 
@@ -193,7 +197,8 @@ export function MessageList({
               role="button"
               tabIndex={dimmed ? -1 : 0}
               aria-disabled={dimmed}
-              onClick={() => !dimmed && onSelect(thread.id)}
+              onClick={() => !dimmed && !swipe.justSwiped() && onSelect(thread.id)}
+              {...(onSwipeDelete && !dimmed ? swipe.handlers(thread.id) : {})}
               onKeyDown={(e) => {
                 if (!dimmed && (e.key === "Enter" || e.key === " ")) onSelect(thread.id);
               }}
@@ -204,6 +209,8 @@ export function MessageList({
                 width: "100%",
                 height: item.size,
                 transform: `translateY(${item.start}px)`,
+                // Sideways drags are the swipe; up and down still scroll the list.
+                ...(onSwipeDelete ? { touchAction: "pan-y" } : {}),
               }}
               // A row leaving the list lets the ones below glide up into its place.
               className={`group absolute inset-x-0 px-2 ${compact ? "pt-5" : "pt-[7px]"} motion-safe:transition-transform motion-safe:duration-200 motion-safe:ease-out ${
@@ -219,9 +226,33 @@ export function MessageList({
                   }`}
                 />
               )}
+              {swipe.id === thread.id && swipe.dx > 0 && (
+                // Behind the row as it moves: where it is going.
                 <div
-                className={`flex h-full items-center gap-3 rounded-lg px-3 ${
-                  selected || checked ? "bg-app-active" : "group-hover:bg-app-hover"
+                  aria-hidden
+                  className={`absolute inset-x-2 bottom-0 flex items-center rounded-lg bg-red-600 pl-5 text-white ${
+                    compact ? "top-5" : "top-[7px]"
+                  }`}
+                >
+                  <span style={{ opacity: Math.min(1, swipe.dx / 80) }}>
+                    <Icon name="trash" size={22} />
+                  </span>
+                </div>
+              )}
+              <div
+                style={
+                  swipe.id === thread.id
+                    ? {
+                        transform: `translateX(${swipe.dx}px)`,
+                        transition: swipe.dragging ? "none" : "transform 180ms ease-out",
+                      }
+                    : undefined
+                }
+                className={`relative flex h-full items-center gap-3 rounded-lg px-3 ${
+                  selected || checked
+                    ? "bg-app-active"
+                    : // Only while it moves: covering the red behind it, in the list's own colour.
+                      `group-hover:bg-app-hover ${swipe.id === thread.id ? "bg-app-surface" : ""}`
                 }`}
               >
                 {/* Avatar, replaced by a selection checkbox on avatar-hover or once
@@ -423,3 +454,72 @@ export function MessageList({
     </div>
   );
 }
+
+
+// --- phone: swipe a row right to delete it ----------------------------------------
+
+// Past this share of the row's width, letting go deletes; short of it the row
+// springs back. A drag must also start clearly sideways, or it is a scroll.
+const SWIPE_DELETE_SHARE = 0.35;
+const SWIPE_START_PX = 12;
+
+function useSwipeToDelete(onDelete?: (id: string) => void) {
+  const [state, setState] = useState<{ id: string; dx: number; dragging: boolean } | null>(null);
+  const start = useRef<{ id: string; x: number; y: number; width: number; active: boolean } | null>(
+    null,
+  );
+  const swipedAt = useRef(0);
+
+  const handlers = (id: string) => ({
+    onPointerDown: (e: React.PointerEvent<HTMLDivElement>) => {
+      if (e.pointerType === "mouse" || !onDelete) return;
+      start.current = { id, x: e.clientX, y: e.clientY, width: e.currentTarget.offsetWidth, active: false };
+    },
+    onPointerMove: (e: React.PointerEvent<HTMLDivElement>) => {
+      const s = start.current;
+      if (!s || s.id !== id) return;
+      const dx = e.clientX - s.x;
+      const dy = e.clientY - s.y;
+      if (!s.active) {
+        if (Math.abs(dy) > SWIPE_START_PX && Math.abs(dy) > Math.abs(dx)) {
+          start.current = null; // a scroll
+          return;
+        }
+        if (dx < SWIPE_START_PX || dx < Math.abs(dy) * 1.5) return;
+        s.active = true;
+        e.currentTarget.setPointerCapture(e.pointerId);
+      }
+      setState({ id, dx: Math.max(0, dx), dragging: true });
+    },
+    onPointerUp: (e: React.PointerEvent<HTMLDivElement>) => {
+      const s = start.current;
+      start.current = null;
+      if (!s || !s.active || s.id !== id) return;
+      swipedAt.current = Date.now();
+      const dx = Math.max(0, e.clientX - s.x);
+      if (dx > s.width * SWIPE_DELETE_SHARE) {
+        setState({ id, dx: s.width, dragging: false }); // off it goes
+        window.setTimeout(() => {
+          setState(null);
+          onDelete?.(id);
+        }, 180);
+      } else {
+        setState({ id, dx: 0, dragging: false }); // back it comes
+        window.setTimeout(() => setState((cur) => (cur && cur.id === id && cur.dx === 0 ? null : cur)), 200);
+      }
+    },
+    onPointerCancel: () => {
+      start.current = null;
+      setState((cur) => (cur && cur.id === id ? { id, dx: 0, dragging: false } : cur));
+    },
+  });
+
+  return {
+    id: state?.id ?? null,
+    dx: state?.dx ?? 0,
+    dragging: state?.dragging ?? false,
+    handlers,
+    // The click that ends a swipe is not a tap on the row.
+    justSwiped: () => Date.now() - swipedAt.current < 400,
+  };
+}

frontend/src/components/mail/MailboxDisplay.tsx

@@ -10,7 +10,14 @@ import { ReadingPanePicker } from "./ReadingPanePicker";
  * closes the popover; the dividers switch applies at once and leaves it open;
  * ✕, Escape or a click elsewhere closes it.
  */
-export function MailboxDisplay({ onClose }: { onClose: () => void }) {
+export function MailboxDisplay({
+  onClose,
+  layouts = true,
+}: {
+  onClose: () => void;
+  /** The reading-pane layouts; off on a phone, which always uses one panel. */
+  layouts?: boolean;
+}) {
   const t = useT();
   const ref = useRef<HTMLDivElement>(null);
 
@@ -32,7 +39,7 @@ export function MailboxDisplay({ onClose }: { onClose: () => void }) {
       ref={ref}
       role="dialog"
       aria-label={t("display.title")}
-      className="absolute right-0 top-full z-30 mt-1 w-[360px] rounded-xl border border-app-border bg-app-elevated p-4 shadow-2xl"
+      className="absolute right-0 top-full z-30 mt-1 w-[360px] max-w-[calc(100vw-1.5rem)] rounded-xl border border-app-border bg-app-elevated p-4 shadow-2xl"
     >
       <div className="mb-3 flex items-center justify-between">
         <h3 className="text-lg font-semibold text-app-fg">{t("display.title")}</h3>
@@ -48,11 +55,17 @@ export function MailboxDisplay({ onClose }: { onClose: () => void }) {
           </svg>
         </button>
       </div>
+      {layouts ? (
+        <>
           <p className="mb-2 text-[13px] font-medium text-app-fg">{t("display.readingPane")}</p>
           <ReadingPanePicker onPick={onClose} />
           <div className="mt-4 border-t border-app-border pt-3">
             <ListDividersOption />
           </div>
+        </>
+      ) : (
+        <ListDividersOption />
+      )}
     </div>
   );
 }

frontend/src/i18n/en.ts

@@ -184,6 +184,7 @@ export const en = {
   "panel.noAttachments": "No attachments",
   "panel.download": "Download",
   "mail.emptyConfirm": "Permanently delete everything in this folder? This can't be undone.",
+  "mail.movedToTrash": "Moved to Trash",
   "mail.loadFailed": "Couldn't load this message.",
   "mail.imagesBlocked": "Images from this sender are blocked.",
   "mail.loadImages": "Load images",

frontend/src/routes/MailLayout.tsx

@@ -581,6 +581,50 @@ export function MailLayout() {
   }, [threadsQuery.data]);
   const listArchive = (id: string) => listMove(id, api.archiveThread);
   const listTrash = (id: string) => listMove(id, api.trashThread);
+  // Phone: a conversation swiped right goes to Trash — after a short Undo
+  // window, like Undo send. Until then it is only hidden, so Undo just shows it
+  // again (moving it back from Trash could race the server's move).
+  const SWIPE_UNDO_MS = 5000;
+  const pendingSwipes = useRef(new Map<string, number>());
+  const swipeTrash = (id: string) => {
+    setHiddenIds((prev) => new Set(prev).add(id));
+    if (id === threadId) navigate("/mail");
+    const timer = window.setTimeout(() => {
+      pendingSwipes.current.delete(id);
+      void listMove(id, api.trashThread);
+    }, SWIPE_UNDO_MS);
+    pendingSwipes.current.set(id, timer);
+    window.dispatchEvent(
+      new CustomEvent("webmail:toast", {
+        detail: {
+          text: t("mail.movedToTrash"),
+          ms: SWIPE_UNDO_MS,
+          action: {
+            label: t("compose.undo"),
+            run: () => {
+              window.clearTimeout(pendingSwipes.current.get(id));
+              pendingSwipes.current.delete(id);
+              setHiddenIds((prev) => {
+                const next = new Set(prev);
+                next.delete(id);
+                return next;
+              });
+            },
+          },
+        },
+      }),
+    );
+  };
+  // Leaving before the toast is gone still deletes what was swiped.
+  useEffect(
+    () => () => {
+      for (const [id, timer] of pendingSwipes.current) {
+        window.clearTimeout(timer);
+        void api.trashThread(id);
+      }
+    },
+    [],
+  );
   const listRestore = (id: string) => listMove(id, api.restoreThread);
   const listDeletePermanent = (id: string) => listMove(id, api.deleteThreadPermanent);
   const listTogglePin = async (id: string, pinned: boolean) => {
@@ -1166,8 +1210,8 @@ export function MailLayout() {
                       >
                         {t("mail.markAllRead")}
                       </button>
-                      {/* A phone always reads in a single panel: nothing to choose. */}
-                      {!mobile && (
+                      {/* On a phone it holds only the dividing lines: it always reads in a
+                          single panel, so there is no layout to choose. */}
                       <button
                         className="flex w-full items-center px-3 py-2 text-left text-[13px] text-app-fg hover:bg-app-hover"
                         onClick={() => {
@@ -1177,11 +1221,10 @@ export function MailLayout() {
                       >
                         {t("display.title")}
                       </button>
-                      )}
                     </div>
                   </>
                 )}
-                {displayOpen && <MailboxDisplay onClose={closeDisplay} />}
+                {displayOpen && <MailboxDisplay onClose={closeDisplay} layouts={!mobile} />}
               </div>
             </div>
           </div>
@@ -1247,6 +1290,9 @@ export function MailLayout() {
               dimmedIds={dimmedIds}
               onToggleCheck={toggleCheck}
               compact={mobile}
+              // Phone: swipe right to delete — not in Trash (that would be for
+              // good) and not offline (nothing could be moved).
+              onSwipeDelete={mobile && currentFolder !== "trash" && !offline ? swipeTrash : undefined}
             />
           )}
         </div>