#cmux 0.64.14: iPhone Companion App (Beta), Cross-Window Workspace Drag, Out-of-Process Custom Sidebars

June 6, 2026

iPhone Companion App (Beta). Pair an iPhone with your Mac from the new Mobile Connect window and attach to your terminals from your phone, with opt-in forwarding of terminal notifications. The iOS beta ships on TestFlight as cmux BETA.

Cross-Window Workspace Drag. Drag a workspace out of one window's sidebar and drop it into another window's sidebar to move it, including grouped workspaces.

Out-of-Process Custom Sidebars. Custom sidebar extensions now run in their own process with an isolated interpreter, so a broken sidebar can't hang or crash cmux, and the interpreter covers a broader set of SwiftUI primitives.

Browser Polish. The omnibar selects the whole URL on the first focusing click (Chrome parity), browser chrome scales with the tab bar font size, a typing beachball with large histories is fixed, and hidden panes no longer stop actively-playing audio or video.

Agent Session Fixes. Claude resume keeps cmux hooks attached so notifications and status tracking survive resumes, Agent Hibernation works for node-backed Claude sessions, and Codex resume preserves CODEX_HOME and pane order.

Added

iPhone companion app (beta): pair an iPhone from the new Mobile Connect window (also in the command palette) and attach to your Mac's terminals from your phone, with a configurable pairing port and opt-in forwarding of terminal notifications; the iOS beta ships on TestFlight as cmux BETA (#5079, #5493, #5489, #5518)
Drag a workspace into another window's sidebar to move it between windows, including grouped workspaces (#5399)
Sign In and Sign Out commands in the command palette (#5529)
OMP agent hook integration with notifications and session restore via cmux hooks omp (#5413) -- thanks @joshrzemien!

Changed

Custom sidebar extensions now run out-of-process with an isolated interpreter, so a broken sidebar can't hang or crash the app (#5294, #5382) -- thanks @azooz2003-bit!
Broader SwiftUI primitive coverage in the custom sidebar interpreter (#5275) -- thanks @azooz2003-bit!
Browser omnibar: the first click that focuses the address bar selects the whole URL, later clicks place the caret (Chrome parity) (#5462, #5352)
Browser chrome (omnibar font and toolbar icons) scales with the tab bar font size (#5464)
Sidebar workspace group headers scale with the sidebar font size (#5401)
Agent Hibernation defaults to a 5-second idle window when enabled (#5449)
Tighter fuzzy filtering for skill suggestions in the terminal textbox (#5348)

Fixed

Keep actively-playing audio and video in browser panes alive when the pane is hidden (#5412, #5441)
Fix a typing beachball in the browser omnibar with large browsing histories (#5397)
Fix the main window refusing to resize narrower than its current width (#5474)
Fix the sidebar close button hidden under wrapped workspace titles (#5488)
Fix notification sound selection so the picker previews the selected sound and notifications play it (#5480)
Restore the menu bar icon dropdown menu on click (#5451)
Fix OSC control sequences (e.g. terminal background color) printed as literal text when sent via cmux send (#5509)
Fix native Claude resume dropping cmux hooks, so notifications and status tracking keep working on resumed sessions (#5430)
Fix Agent Hibernation for node-backed Claude sessions (#5433)
Codex resume hardening: keep restored surfaces from jumbling and preserve CODEX_HOME so non-default Codex homes resume correctly (#5351)
Fix Cmd +/- zoom in the browser and Markdown viewer on non-US keyboard layouts (#5394)
Preserve syntax highlighting on changed lines in the diff viewer (#5415)
Fix a stale group name in the window title bar after renaming a workspace group (#5408)
Fix the Dock sidebar not rendering after closing and reopening it (#5437)
Fix OMO subagent pane respawn through the tmux compatibility shim (#5465) -- thanks @leodiegoo for the report!
Reduce sidebar git activity by coalescing repeated metadata probes (#5402)

Contributors