v0.2.28

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 What changed in each RustBox release, written for the people who use and run it. Technical details are in the [documentation](docs/).
 
+## 0.2.28
+
+- Replying to a message you sent no longer addresses the reply back to yourself; RustBox chooses the other thread participant(s), including when aliases/identities are used.
+- The reader now has a direct toggle between thread view and a single-message view; the choice uses the existing mailbox thread preference.
+- Polish text decoding is more tolerant of legacy mail: RFC 2047 ISO-8859-2 subjects and common UTF-8/Windows-1252 or ISO-8859-2/Western-Latin mojibake are repaired in headers, bodies and cached message previews.
+
 ## 0.2.27
 
 - Monochrome mode now creates a custom copy when editing a predefined interface style, just like direct colour changes.

Cargo.lock

@@ -3506,7 +3506,7 @@ dependencies = [
 
 [[package]]
 name = "rustbox"
-version = "0.2.27"
+version = "0.2.28"
 dependencies = [
  "aes-gcm",
  "async-imap",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rustbox"
-version = "0.2.27"
+version = "0.2.28"
 edition = "2024"
 rust-version = "1.99.1"
 license = "AGPL-3.0-only"

README.md

@@ -1,4 +1,4 @@
-# RustBox 0.2.27
+# RustBox 0.2.28
 
 **Fast, self-hosted webmail written in Rust.** RustBox connects to any IMAP/SMTP server and ships as one executable with the whole interface built in, so there is no Node.js, PHP or separate frontend to deploy.
 

RELEASE-MANIFEST.txt

@@ -1,4 +1,9 @@
-RustBox 0.2.27 release manifest
+RustBox 0.2.28 release manifest
+
+0.2.28 release changes:
+- replies to own sent messages target the other participant(s), with account aliases/identities treated as own addresses
+- reader toolbar toggles between threaded and single-message presentation using the persisted mailbox `thread_mode` preference
+- legacy Polish text repair covers common UTF-8/Windows-1252 and ISO-8859-2/Western-Latin mojibake in headers, bodies and cached summaries/details; exact ISO-8859-2 folded-subject coverage added
 
 0.2.27 release changes:
 - predefined styles promote to a custom copy when monochrome mode is changed
@@ -126,14 +131,14 @@ Docker examples:
 
 Operations/docs:
 - standalone `scripts/migrate_roundcube.py` imports Roundcube contacts/identities using RustBox config.toml and supports SQLite/MySQL/PostgreSQL targets
-- README.md documents 0.2.27 configuration
+- README.md documents 0.2.28 configuration
 - docker/README.md documents Compose variants
 - docs/STORAGE_SEARCH_OPERATIONS.md documents failure modes, shared-storage requirements and migration behavior
 - TODO.md leaves live SILO/MinIO/AWS/Ceph and real multi-node acceptance validation explicitly pending
 
 Build/release metadata:
 - `scripts/package-release.sh` runs the full Rust release gate before creating ZIP/SHA256 artifacts
-- Cargo.toml version = 0.2.27
+- Cargo.toml version = 0.2.28
 - rust-toolchain.toml pins Rust 1.99.1
 - Cargo.lock is retained for reproducible application builds; the release gate generates it only when missing
 - CI and scripts/build-release.sh use the retained Cargo.lock (generating it only if missing), then run locked tests/Clippy/release build

RELEASE-VALIDATION.txt

@@ -1,7 +1,7 @@
-RustBox 0.2.27 - final source validation
+RustBox 0.2.28 - final source validation
 
-0.2.27 scope:
-- monochrome preset promotion, wider subject presentation with tooltip, non-reserving hover actions, reader-only popup embedding, adaptive HTML-mail light/dark inference from the actual reader surface, graphical per-folder IMAP storage usage, plus the 0.2.26 licensing/documentation baseline
+0.2.28 scope:
+- correct reply recipients for own sent messages in threads, reader thread/single-message toggle, and stronger Polish legacy-encoding/mojibake repair, plus the 0.2.27 mail-list and appearance baseline
 
 0.2.25 scope:
 - filters: apply now on existing messages (`POST /api/filters/match`, IMAP UID SEARCH bounds + cache), exceptions, new conditions and actions, templates, missing-folder creation, "always move from this sender"
@@ -67,15 +67,17 @@ RustBox 0.2.27 - final source validation
 - Composing shows only compact attachment/message size-limit values on one line
 - 0.2.9 realtime notification gating, browser shortcut preservation and 300-message defaults remain intact
 - V047-V052 are consolidated into compatibility baseline V052; V053 adds `skin_depth` and `skin_gradients`; V054 adds the theme schedule and account colour; V055 is next
-- version metadata identifies 0.2.27
+- version metadata identifies 0.2.28
 
 Completed in this environment:
-- offline release validator: scripts/validate-release-static.py (455/455 checks passed)
+- offline release validator: scripts/validate-release-static.py (458/458 checks passed)
 - browser JavaScript assembled in manifest order passes `node --check`
+- reply-recipient helper smoke test covers own-account, alias and normal incoming-message replies
+- supplied legacy Polish `.eml` decodes to the expected ISO-8859-2 subject and UTF-8 quoted-printable body in an independent MIME parser check
 - all JSON files parse successfully
 - Python helper scripts compile successfully
 - shell scripts pass `bash -n`
-- release metadata consistently identifies 0.2.27
+- release metadata consistently identifies 0.2.28
 - V052 baseline consolidation plus the V053 skin-depth migration are validated offline
 - 0.2.25 filter UI (apply now, run now, always move from sender), context submenus and preset editing exercised in Playwright against a mocked API; the 0.2.24 styles rendered at standard and immersive depth with gradients on and off; earlier: all 37 interface styles rendered in light and dark at the immersive depth against a mocked API (Playwright), with no page errors
 

docs/IMPLEMENTATION_STATUS.md

@@ -1,7 +1,13 @@
-# RustBox 0.2.27 - implementation status
+# RustBox 0.2.28 - implementation status
 
 - Draft saves are realtime-silent: Drafts folder/list updates continue, but saving a draft does not surface as a new-mail notification.
-This file tracks the `0.2.27` source snapshot. Storage/search scope and outstanding acceptance work are tracked in `TODO.md`. A feature is only listed as implemented when working code exists in this source tree; partial items are called out explicitly.
+This file tracks the `0.2.28` source snapshot. Storage/search scope and outstanding acceptance work are tracked in `TODO.md`. A feature is only listed as implemented when working code exists in this source tree; partial items are called out explicitly.
+
+## 0.2.28 thread replies and legacy Polish mail decoding
+
+- Reply composition detects all configured account/identity addresses; replying to an own sent message selects the first non-own recipient and Reply all keeps the remaining external participants.
+- The reader toolbar toggles the existing `thread_mode` mailbox preference between threaded and flat/single-message presentation.
+- Header/body rendering repairs common Polish mojibake while retaining RFC 2047 charset decoding; cached summaries/details are normalized on output so old cached rows benefit without a schema migration.
 
 ## 0.2.27 mail-list and appearance polish
 

scripts/validate-release-static.py

@@ -205,6 +205,9 @@ require('imap_source' in compose_js and 'imap_attachments' in compose_js and 'lo
 require('Attachment::new_inline_with_name' in drafts_rs and 'Attachment::new_inline_with_name' in read("src/smtp/builder.rs"), "inline MIME parts preserve attachment filenames in saved drafts and sent messages")
 require('mail_parser::MessageParser::default().parse(synthetic.as_bytes())' in read("src/imap/parse.rs") and 'decode_header_bytes' in read("src/imap/parse.rs"), "RFC 2047 header decoding uses mail-parser and tolerant envelope byte handling")
 require('encoding_rs::Encoding::for_label' in read("src/imap/parse.rs") and 'decodes_polish_rfc2047_subjects' in read("src/imap/parse.rs"), "Polish UTF-8/ISO-8859-2/Windows-1250 header decoding is covered")
+require('repair_common_mojibake' in read("src/imap/parse.rs") and 'Ubezpieczenie_nieruchomo=B6ci' in read("src/imap/parse.rs") and 'objętość 12 m³' in read("src/imap/parse.rs"), "legacy Polish mojibake repair covers the supplied ISO-8859-2 pattern without rewriting normal m³ text")
+require('function replyRecipientsForMessage(detail)' in compose_js and '...(state.identities || []).map((identity) => identity.email)' in compose_js and 'const replyRecipients = replyRecipientsForMessage(detail);' in compose_js, "replying to an own sent message can target non-own thread participants and recognizes identities")
+require('id="thread-mode-btn"' in index_html and 'function toggleReaderThreadMode()' in reader_js and 'thread_mode: next' in reader_js and '$(("#thread-mode-btn"))' not in bindings_js and '$("#thread-mode-btn").addEventListener("click", toggleReaderThreadMode);' in bindings_js, "reader exposes a persisted threaded/single-message toggle")
 require('let is_pdf = response_content_type_is(&response, "application/pdf");' in read("src/routes/mod.rs") and 'HeaderValue::from_static("SAMEORIGIN")' in read("src/routes/mod.rs") and "HeaderValue::from_static(\"frame-ancestors 'self'\")" in read("src/routes/mod.rs"), "security headers allow same-origin framing for inline PDF previews only")
 index_html = read("src/web/index.html")
 require('class="compose-limit-summary"' in index_html and 'Per-file upload limit set with' not in index_html and 'Hard limit for the complete RFC822/MIME message' not in index_html, "Composing shows compact raw size limits without implementation details")

src/imap/client.rs

@@ -4,7 +4,7 @@ use futures::StreamExt;
 use super::connection::map_imap_error;
 use super::parse::{
     decode_header_bytes, flag_to_string, has_attachments, imap_address_to_email,
-    name_attribute_to_string,
+    name_attribute_to_string, repair_common_mojibake,
 };
 
 pub use super::error::ImapError;
@@ -596,7 +596,9 @@ impl ImapClient for RealImapClient {
                     ImapError::ProtocolError("failed to parse RFC822 message".to_string())
                 })?;
 
-            let text_plain: Option<String> = parsed.body_text(0).map(|s| s.to_string());
+            let text_plain: Option<String> = parsed
+                .body_text(0)
+                .map(|s| repair_common_mojibake(s.as_ref()));
 
             let has_html_part = parsed.parts.iter().any(|part| {
                 part.content_type()
@@ -604,7 +606,9 @@ impl ImapClient for RealImapClient {
             });
 
             let text_html: Option<String> = if has_html_part {
-                parsed.body_html(0).map(|s| s.to_string())
+                parsed
+                    .body_html(0)
+                    .map(|s| repair_common_mojibake(s.as_ref()))
             } else {
                 None
             };

src/imap/parse.rs

@@ -1,5 +1,97 @@
 use super::types::EmailAddress;
 
+fn mojibake_score(input: &str) -> usize {
+    input
+        .chars()
+        .map(|ch| match ch {
+            '\u{fffd}' => 8,
+            'Ã' | 'Â' | 'Ä' | 'Å' | 'â' | '±' | 'æ' | 'ê' | '³' | 'ñ' | '¶' | '¿' | '¼' | '¡'
+            | 'Æ' | 'Ê' | '£' | 'Ñ' | '¦' | '¯' | '¬' | '›' | 'œ' | 'ž' => 1,
+            _ => 0,
+        })
+        .sum()
+}
+
+fn polish_letter_count(input: &str) -> usize {
+    input
+        .chars()
+        .filter(|ch| "ąćęłńóśźżĄĆĘŁŃÓŚŹŻ".contains(*ch))
+        .count()
+}
+
+fn windows_1252_bytes(input: &str) -> Option<Vec<u8>> {
+    let (bytes, _, had_errors) = encoding_rs::WINDOWS_1252.encode(input);
+    (!had_errors).then(|| bytes.into_owned())
+}
+
+fn looks_like_polish_latin2_mojibake(input: &str) -> bool {
+    const MARKERS: &str = "±æê³ñ¶¿¼¡ÆʣѦ¯¬";
+    let marker_count = input.chars().filter(|ch| MARKERS.contains(*ch)).count();
+    if marker_count >= 2 {
+        return true;
+    }
+    if marker_count == 0 {
+        return false;
+    }
+
+    input
+        .split(|ch: char| !(ch.is_ascii_alphabetic() || MARKERS.contains(ch)))
+        .any(|token| {
+            token.chars().count() >= 4
+                && token.chars().filter(|ch| ch.is_ascii_alphabetic()).count() >= 3
+                && token.chars().any(|ch| MARKERS.contains(ch))
+        })
+}
+
+/// Repairs the two mojibake forms most often seen in older Polish mail:
+/// UTF-8 interpreted as Windows-1252 and ISO-8859-2 interpreted as Western Latin.
+/// A candidate is accepted only when it reduces suspicious characters and does
+/// not lose Polish letters, which keeps normal Unicode mail unchanged.
+pub(crate) fn repair_common_mojibake(input: &str) -> String {
+    let mut best = input.to_string();
+
+    for _ in 0..2 {
+        let current = best.clone();
+        let current_score = mojibake_score(&current);
+        if current_score == 0 {
+            break;
+        }
+        let current_polish = polish_letter_count(&current);
+        let Some(bytes) = windows_1252_bytes(&current) else {
+            break;
+        };
+
+        let mut candidates = Vec::new();
+        if let Ok(candidate) = String::from_utf8(bytes.clone()) {
+            candidates.push(candidate);
+        }
+        if looks_like_polish_latin2_mojibake(&current)
+            && let Some(encoding) = encoding_rs::Encoding::for_label(b"iso-8859-2")
+        {
+            let (candidate, _, _) = encoding.decode(&bytes);
+            candidates.push(candidate.into_owned());
+        }
+
+        let mut improved = false;
+        for candidate in candidates {
+            let candidate_score = mojibake_score(&candidate);
+            let candidate_polish = polish_letter_count(&candidate);
+            if candidate_score < mojibake_score(&best)
+                && candidate_polish >= current_polish
+                && (candidate_polish > current_polish || candidate_score == 0)
+            {
+                best = candidate;
+                improved = true;
+            }
+        }
+        if !improved {
+            break;
+        }
+    }
+
+    best
+}
+
 pub(crate) fn name_attribute_to_string(attr: &async_imap::types::NameAttribute<'_>) -> String {
     use async_imap::types::NameAttribute;
     match attr {
@@ -35,7 +127,7 @@ pub(crate) fn flag_to_string(flag: &async_imap::types::Flag<'_>) -> String {
 
 pub(crate) fn decode_rfc2047(input: &str) -> String {
     if !input.contains("=?") {
-        return input.to_string();
+        return repair_common_mojibake(input);
     }
 
     // Let mail-parser handle RFC 2047 encoded words first. It supports a wider
@@ -47,7 +139,7 @@ pub(crate) fn decode_rfc2047(input: &str) -> String {
     {
         let decoded = subject.to_string();
         if !decoded.is_empty() && decoded != input {
-            return decoded;
+            return repair_common_mojibake(&decoded);
         }
     }
 
@@ -101,7 +193,7 @@ pub(crate) fn decode_rfc2047(input: &str) -> String {
     }
 
     result.push_str(remaining);
-    result
+    repair_common_mojibake(&result)
 }
 
 pub(crate) fn decode_quoted_printable_header(input: &str) -> Option<Vec<u8>> {
@@ -143,11 +235,11 @@ pub(crate) fn decode_header_bytes(bytes: &[u8]) -> String {
     {
         let decoded = subject.to_string();
         if !decoded.is_empty() {
-            return decoded;
+            return repair_common_mojibake(&decoded);
         }
     }
     let text = String::from_utf8_lossy(bytes);
-    decode_rfc2047(&text)
+    repair_common_mojibake(&decode_rfc2047(&text))
 }
 
 pub(crate) fn imap_address_to_email(
@@ -220,5 +312,25 @@ mod tests {
             decode_rfc2047("=?windows-1250?b?WmG/87PmIGfqnGy5IGphn/E=?="),
             "Zażółć gęślą jaźń"
         );
+        assert_eq!(
+            decode_rfc2047(
+                "=?ISO-8859-2?Q?Ubezpieczenie_nieruchomo=B6ci_-_?= =?ISO-8859-2?Q?bliski_termin_p=B3atno=B6ci_sk=B3adki?="
+            ),
+            "Ubezpieczenie nieruchomości - bliski termin płatności składki"
+        );
+    }
+
+    #[test]
+    fn repairs_common_polish_mojibake() {
+        assert_eq!(
+            repair_common_mojibake("Ubezpieczenie nieruchomo¶ci - bliski termin p³atno¶ci sk³adki"),
+            "Ubezpieczenie nieruchomości - bliski termin płatności składki"
+        );
+        assert_eq!(
+            repair_common_mojibake("Dzień dobry, składka za nieruchomość"),
+            "Dzień dobry, składka za nieruchomość"
+        );
+        assert_eq!(repair_common_mojibake("Åsa"), "Åsa");
+        assert_eq!(repair_common_mojibake("objętość 12 m³"), "objętość 12 m³");
     }
 }

src/routes/messages/mod.rs

@@ -16,6 +16,7 @@ use crate::db::header_sync::HeaderSync;
 use crate::email_theme;
 use crate::error::AppError;
 use crate::imap::client::{ImapClient, ImapCredentials};
+use crate::imap::parse::repair_common_mojibake;
 use crate::realtime::events::{EventBus, MailEvent, MessageFlagChange};
 use crate::routes::folder_counts;
 use crate::search::engine::{IndexableMessage, SearchEngine, UserIndex};
@@ -403,15 +404,15 @@ pub async fn list_messages(
             MessageSummary {
                 uid: m.uid,
                 folder: m.folder,
-                subject: m.subject,
+                subject: repair_common_mojibake(&m.subject),
                 from_address: m.from_address,
-                from_name: m.from_name,
+                from_name: repair_common_mojibake(&m.from_name),
                 to_addresses: m.to_addresses,
                 date: m.date,
                 flags: m.flags,
                 size: m.size,
                 has_attachments: m.has_attachments,
-                snippet: m.snippet,
+                snippet: repair_common_mojibake(&m.snippet),
                 reaction: m.reaction,
                 tags: msg_tags,
             }
@@ -1024,9 +1025,9 @@ pub async fn get_message(
             let indexable = IndexableMessage {
                 uid: msg.uid,
                 folder: msg.folder,
-                subject: msg.subject,
+                subject: repair_common_mojibake(&msg.subject),
                 from_address: msg.from_address,
-                from_name: msg.from_name,
+                from_name: repair_common_mojibake(&msg.from_name),
                 to_addresses: msg.to_addresses,
                 body_text: text.clone(),
                 date_epoch: crate::db::messages::parse_date_to_epoch_public(&msg.date),
@@ -1049,6 +1050,9 @@ pub async fn get_message(
         )
     };
 
+    let body_html = body_html.map(|html| repair_common_mojibake(&html));
+    let body_text = body_text.map(|text| repair_common_mojibake(&text));
+
     let msg = db::messages::get_single_message(&conn, &folder, uid)
         .map_err(|e| AppError::InternalError(format!("Database error: {e}")))?;
 
@@ -1058,7 +1062,7 @@ pub async fn get_message(
             let parsed = mail_parser::MessageParser::default().parse(raw_headers.as_bytes());
             let subject = parsed
                 .as_ref()
-                .and_then(|p| p.subject().map(|s| s.to_string()))
+                .and_then(|p| p.subject().map(repair_common_mojibake))
                 .unwrap_or_default();
             let (from_address, from_name) = parsed
                 .as_ref()
@@ -1070,7 +1074,10 @@ pub async fn get_message(
                                 .as_ref()
                                 .map(|s| s.to_string())
                                 .unwrap_or_default(),
-                            a.name.as_ref().map(|s| s.to_string()).unwrap_or_default(),
+                            a.name
+                                .as_ref()
+                                .map(|s| repair_common_mojibake(s.as_ref()))
+                                .unwrap_or_default(),
                         )
                     }),
                     _ => None,
@@ -1145,16 +1152,16 @@ pub async fn get_message(
             folder: m.folder,
             message_id: m.message_id,
             in_reply_to: m.in_reply_to,
-            subject: m.subject,
+            subject: repair_common_mojibake(&m.subject),
             from_address: m.from_address,
-            from_name: m.from_name,
+            from_name: repair_common_mojibake(&m.from_name),
             to_addresses: m.to_addresses,
             cc_addresses: m.cc_addresses,
             date: m.date,
             flags: m.flags,
             size: m.size,
             has_attachments: m.has_attachments,
-            snippet: m.snippet,
+            snippet: repair_common_mojibake(&m.snippet),
         })
         .collect();
 
@@ -1164,9 +1171,9 @@ pub async fn get_message(
         message_id: msg.message_id.clone(),
         in_reply_to: msg.in_reply_to.clone(),
         references: msg.references_header.clone(),
-        subject: msg.subject,
+        subject: repair_common_mojibake(&msg.subject),
         from_address: msg.from_address,
-        from_name: msg.from_name,
+        from_name: repair_common_mojibake(&msg.from_name),
         to_addresses: parse_address_list(&msg.to_addresses),
         cc_addresses: parse_address_list(&msg.cc_addresses),
         date: msg.date,

src/web/i18n/pl.json

@@ -211,7 +211,7 @@
     "Prefer HTML": "Preferuj HTML",
     "Threads": "Wątki",
     "Threaded": "Wątki",
-    "Flat": "Płasko",
+    "Flat": "Pojedyncze wiadomości",
     "Default sort": "Domyślne sortowanie",
     "Newest first": "Najnowsze najpierw",
     "Oldest first": "Najstarsze najpierw",
@@ -846,6 +846,9 @@
     "No message selected": "Nie wybrano wiadomości",
     "Select a message from the list.": "Wybierz wiadomość z listy.",
     "Thread": "Wątek",
+    "Single message": "Pojedyncza wiadomość",
+    "Show single message": "Pokaż pojedynczą wiadomość",
+    "Show thread": "Pokaż wątek",
     "Remote images are blocked.": "Zdalne obrazy są zablokowane.",
     "Load images": "Wczytaj obrazy",
     "Trust sender": "Zaufaj nadawcy",

src/web/index.html

@@ -233,6 +233,10 @@
               aria-label="Open message full screen" aria-pressed="false"><svg>
                 <use href="__RUSTBOX_ASSET_PREFIX__/assets/icons.svg#icon-external-link"></use>
               </svg></button>
+            <button id="thread-mode-btn" class="button quiet hidden" type="button" title="Show single message"
+              aria-label="Show single message" aria-pressed="true"><svg>
+                <use href="__RUSTBOX_ASSET_PREFIX__/assets/icons.svg#icon-list"></use>
+              </svg><span id="thread-mode-label">Single message</span></button>
             <button id="reply-btn" class="button quiet" type="button"><svg>
                 <use href="__RUSTBOX_ASSET_PREFIX__/assets/icons.svg#icon-reply"></use>
               </svg><span data-i18n="reply">Reply</span></button>

src/web/js/40-messages-reader.js

@@ -668,11 +668,46 @@ function scheduleMarkRead(detail) {
   if (delay === 0) run(); else state.markReadTimer = setTimeout(run, delay);
 }
 
+function updateThreadModeButton(detail) {
+  const button = $("#thread-mode-btn");
+  const label = $("#thread-mode-label");
+  if (!button || !label) return;
+  const hasThread = (detail?.thread || []).length > 1;
+  const threaded = state.mailPrefs.thread_mode !== "flat";
+  button.classList.toggle("hidden", !hasThread);
+  button.setAttribute("aria-pressed", String(threaded));
+  const action = threaded ? "Show single message" : "Show thread";
+  button.title = trText(action);
+  button.setAttribute("aria-label", trText(action));
+  label.textContent = trText(threaded ? "Single message" : "Thread");
+}
+
+async function toggleReaderThreadMode() {
+  if (!state.currentDetail || (state.currentDetail.thread || []).length <= 1) return;
+  const previous = state.mailPrefs.thread_mode || "threaded";
+  const next = previous === "flat" ? "threaded" : "flat";
+  state.mailPrefs.thread_mode = next;
+  const select = $("#mail-pref-thread-mode");
+  if (select) select.value = next;
+  renderThread(state.currentDetail);
+  try {
+    state.mailPrefs = await request("/settings/mailbox", { method: "PUT", body: JSON.stringify({ thread_mode: next }) });
+    if (select) select.value = state.mailPrefs.thread_mode || next;
+    renderThread(state.currentDetail);
+  } catch (error) {
+    state.mailPrefs.thread_mode = previous;
+    if (select) select.value = previous;
+    renderThread(state.currentDetail);
+    toast(error.message, "error");
+  }
+}
+
 function renderThread(detail) {
   const thread = detail.thread || [];
   const section = $("#thread-section");
   const list = $("#thread-list");
   list.replaceChildren();
+  updateThreadModeButton(detail);
   const enabled = state.mailPrefs.thread_mode !== "flat";
   section.classList.toggle("hidden", !enabled || thread.length <= 1);
   if (!enabled || thread.length <= 1) return;

src/web/js/50-compose.js

@@ -94,7 +94,32 @@ function quoteTextAsHtml(text) {
 }
 
 function ownAddressSet() {
-  return new Set(state.accounts.map((account) => String(account.email || "").trim().toLowerCase()).filter(Boolean));
+  const addresses = [
+    ...(state.accounts || []).map((account) => account.email),
+    ...(state.identities || []).map((identity) => identity.email),
+  ];
+  return new Set(addresses.map((address) => String(address || "").trim().toLowerCase()).filter(Boolean));
+}
+
+function replyRecipientsForMessage(detail) {
+  const own = ownAddressSet();
+  const sender = String(detail?.from_address || "").trim();
+  const senderKey = sender.toLowerCase();
+  const senderIsOwn = senderKey && own.has(senderKey);
+  const recipients = [];
+  const seen = new Set();
+
+  for (const entry of [...(detail?.to_addresses || []), ...(detail?.cc_addresses || [])]) {
+    const address = String(entry?.address || "").trim();
+    const key = address.toLowerCase();
+    if (!address || own.has(key) || key === senderKey || seen.has(key)) continue;
+    seen.add(key);
+    recipients.push(address);
+  }
+
+  if (!senderIsOwn && sender) return { to: sender, cc: recipients };
+  const [to, ...cc] = recipients;
+  return { to: to || sender, cc };
 }
 
 function ensureDraftId() {
@@ -1732,14 +1757,9 @@ function openCompose(mode = "new", options = {}) {
 
   if (detail && (mode === "reply" || mode === "reply-all")) {
     state.composeReplyMeta = { inReplyTo: detail.message_id || null, references: buildReferences(detail) };
-    $("#compose-to").value = detail.from_address || "";
-    if (mode === "reply-all") {
-      const own = ownAddressSet();
-      const cc = [...(detail.to_addresses || []), ...(detail.cc_addresses || [])]
-        .map((entry) => entry.address || "")
-        .filter((address) => address && address.toLowerCase() !== String(detail.from_address || "").toLowerCase() && !own.has(address.toLowerCase()));
-      $("#compose-cc").value = [...new Set(cc)].join(", ");
-    }
+    const replyRecipients = replyRecipientsForMessage(detail);
+    $("#compose-to").value = replyRecipients.to;
+    if (mode === "reply-all") $("#compose-cc").value = replyRecipients.cc.join(", ");
     $("#compose-subject").value = /^re:/i.test(detail.subject || "") ? detail.subject : `Re: ${detail.subject || ""}`;
     const quoteStyle = state.prefs.quoteStyle || "standard";
     const quote = quoteStyle === "none" ? null : el("div", "compose-quote");

src/web/js/95-bindings-boot.js

@@ -382,6 +382,7 @@ function bindEvents() {
   $("#reader-prev").addEventListener("click", () => navigateMessage(-1));
   $("#reader-next").addEventListener("click", () => navigateMessage(1));
   $("#reader-fullscreen").addEventListener("click", toggleReaderFullscreen);
+  $("#thread-mode-btn").addEventListener("click", toggleReaderThreadMode);
   $("#thread-toggle").addEventListener("click", () => {
     state.threadExpanded = !state.threadExpanded;
     localStorage.setItem("rustbox.threadExpanded", String(state.threadExpanded));