cmuxcmux
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Changelog

#cmux 0.64.13: Browser Focus Mode, SSH Agent Forwarding, Custom Sidebars (Beta), Major Stability Fixes

Browser Focus Mode. Browser panes get a focus mode that strips away the surrounding chrome so a single page can take over the pane while you read or work in it.

SSH Agent Forwarding. `cmux ssh` now forwards your local SSH agent, so remote sessions can use your local keys for git pushes and further hops without copying private keys onto the remote.

Vibe-Codable Custom Sidebars (Beta). Build your own sidebar with a runtime Swift interpreter, behind the Beta Features flag. Edit the sidebar source, validate it from the CLI, and reload it live without rebuilding the app.

Browser Mouse Back & Forward. The browser now responds to the dedicated back and forward buttons on a mouse, so side-button navigation works the way it does in a normal browser.

Major Stability & Performance Fixes. Fixed a settings-observation leak that grew the app to 4.4 GB over a day, a browser render loop burning ~39% of the main thread on every CoreAnimation commit, a WebKit crash after sleep/wake, a 100% CPU hang in the Markdown and file-preview editor, and child processes launching under Rosetta on Apple Silicon.

Added
  • Browser focus mode (#4573)
  • SSH agent forwarding for cmux ssh, so remote sessions can use your local SSH keys (#5301)
  • Vibe-codable custom sidebars: a runtime Swift interpreter for building your own sidebar, behind a Beta Features flag, with CLI validation and live reload (#5254, #5327) -- thanks @azooz2003-bit!
  • Browser mouse back and forward button support (#5197)
  • Persisted word-wrap setting for the file editor (#5247)
  • "Open Current Directory in Devin" command (#5288) -- thanks @MaxiAschenbrenner!
  • Live status reporting in the Amp Neo session plugin, driving the cmux tab status bar (#5235) -- thanks @HamptonMakes!
Changed
  • Anchor the textbox autocomplete to the cursor (#5021)
  • Add a font-size popover to the Markdown viewer controls (#5168)
  • Open group config files in your configured editor (#5250)
  • Isolate browser WebKit process pools so one browser pane crashing no longer takes down the others (#4987)
  • Move large scrollback read-text work off the main actor to reduce UI hangs (#5243) -- thanks @azooz2003-bit!
Fixed
  • Fix a settings-observation task leak that grew the app process to 4.4 GB over ~23h (#5310)
  • Fix a browser pane render loop that re-navigated the WebView on every CoreAnimation commit (~39% main-thread CPU) (#5311)
  • Fix a WebKit post-wake crash with sleep/wake-aware hidden-webview discard scheduling (#5315) -- thanks @azooz2003-bit!
  • Fix the Markdown and file-preview text editor hanging at 100% CPU on click or drag-select by forcing a TextKit 1 stack (#5257)
  • Stop cmux from launching child processes under Rosetta on Apple Silicon (#5306) -- thanks @CharlesWiltgen for the report!
  • Recover terminal focus when the first responder is stranded in another window (#5296)
  • Fix the browser address bar so a single click places a caret instead of selecting the whole URL (#5270)
  • Fix copy-mode vim keys (j/k/h/l) swallowed under non-ASCII input sources (Korean, Japanese Kana, Zhuyin) (#5292) -- thanks @pstanton237!
  • Fix terminal copy-mode cursor navigation (#5328)
  • Fix terminal selection on mouse-up while the find overlay is open (#5335)
  • Fix TextBox IME and input-source handling (#5340)
  • Fix the macOS "wants to access data from other apps" prompt on agent session start and quit by moving the control socket out of Application Support (#5176)
  • Fix Codex auto-resume emitting an invalid -s disabled sandbox flag (#5276) -- thanks @taonetm7 for the report!
  • Fix agent session resume cd-ing into the wrong directory after a cwd drift, plus post-kill cwd handling (#5300, #5312)
  • Fix restored cwd bindings after a reboot (#5307)
  • Fix a stale sidebar git branch after cd-ing out of a repo into a non-git directory (#5279)
  • Fix a TextBox teardown crash when toggling the sidebar background (#5317)
  • Fix a workspace-close teardown hang (#5316) -- thanks @azooz2003-bit!
  • Fix the workspace-group "Delete Group" context-menu action being a no-op (#5253)
  • Fix the diff viewer showing a raw CLI error and beeping when there is no diff (#5252)
  • Fix sidebar drag-and-drop frame collection with the lazy (virtualized) sidebar (#5325)
  • Lazy-load file explorer roots to speed up opening the file tree (#5342)
  • Fix Claude workflow resume transcript resolution (#5242) -- thanks @azooz2003-bit!
  • Fix opening the remote SSH file browser (#5241) -- thanks @azooz2003-bit!
  • Fix custom-sidebar extension discovery for tagged builds (#5267) -- thanks @azooz2003-bit!
  • Fix Sparkle update packaging and Claude hook transcript scaling (#5202)