diff --git a/README.md b/README.md
index 5b73f41..796128b 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,7 @@ The tmux server runs in its own unit, so every Claude process lives in **that**
 | Ctrl-b d | Detach (the session keeps running) |
 | Drag | Selects text; it stays highlighted and is copied when you let go. Double-click selects a word, triple-click a line. Clicks on the tmux status line still go to tmux. |
 | Ctrl+C | Copies the selection when there is one; otherwise interrupts as usual |
+| Palette → Close split panes | Removes extra tmux panes (a stray `^b %` split) and keeps Claude. tmux's right-click menus are off. |
 | Ctrl+Shift+C / V | Copy selection / paste |
 | Ctrl+Shift+P | Command palette (also the ⌕ button) |
 | Ctrl+Shift+E | Files pane (Esc: back, then close) |
diff --git a/bin/devdesk b/bin/devdesk
index a10ab5d..ed3ee43 100755
--- a/bin/devdesk
+++ b/bin/devdesk
@@ -15,7 +15,7 @@
 #
 # The web UI calls `devdesk attach --list | --repo NAME | --alerts | --investigate SESSION UID |
 # --upload SESSION FILE BYTES | --new NAME [PROJECT] [--worktree] | --rename OLD NEW | --end NAME |
-# --last-reply NAME | --existing NAME`
+# --last-reply NAME | --unsplit NAME | --existing NAME`
 # through ttyd; those print JSON.
 set -euo pipefail
 
@@ -182,6 +182,25 @@ dd_worktree_end() {
     fi
 }
 
+# --unsplit NAME (devdesk#52): close the extra panes a split left in the session's
+# windows. Each window keeps one pane: Claude's in the claude window, else the
+# first. Prints {ok, closed}.
+cmd_unsplit() {
+    [ $# -eq 1 ] || dd_die "usage: devdesk attach --unsplit NAME"
+    dd_valid_name "$1" || dd_die "invalid session name: $1"
+    { dd_server_up && dd_tmux has-session -t "=$1" 2>/dev/null; } || dd_die "session '$1' isn't running"
+    local win keep pane closed=0
+    while read -r win; do
+        keep=$(dd_tmux list-panes -t "=$1:$win" -F '#{pane_id} #{pane_start_command}' | awk '/devdesk-claude-run/ { print $1; exit }')
+        [ -n "$keep" ] || keep=$(dd_tmux list-panes -t "=$1:$win" -F '#{pane_id}' | head -n 1)
+        while read -r pane; do
+            [ "$pane" = "$keep" ] && continue
+            dd_tmux kill-pane -t "$pane" && closed=$((closed + 1))
+        done < <(dd_tmux list-panes -t "=$1:$win" -F '#{pane_id}')
+    done < <(dd_tmux list-windows -t "=$1" -F '#{window_index}')
+    jq -cMn --argjson c "$closed" '{ok: true, closed: $c}'
+}
+
 cmd_rename() {
     [ $# -eq 2 ] || dd_die "usage: devdesk rename OLD NEW"
     local old=$1 new=$2 running=0
@@ -366,7 +385,7 @@ cmd_attach() {
         dd_linger
         return
         ;;
-    --peek | --search | --last-reply)
+    --peek | --search | --last-reply | --unsplit)
         local action=${1#--}
         shift
         "cmd_${action//-/_}" "$@"
diff --git a/debian/changelog b/debian/changelog
index d2f4b01..3d40a85 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,12 @@
+devdesk (0.10.3) bookworm; urgency=medium
+
+  * No tmux right-click menus (#52). A stray click on one split a pane, or
+    could kill Claude's window. "Close split panes (keeps Claude)" in the
+    command palette, backed by `--unsplit`, removes a split that happened
+    anyway.
+
+ -- Jared Vititoe <jjvititoe1@gmail.com>  Tue, 13 Oct 2026 09:00:00 -0400
+
 devdesk (0.10.2) bookworm; urgency=medium
 
   * Selecting text in the terminal works like a normal terminal (#51). A
diff --git a/share/tmux.conf b/share/tmux.conf
index d861252..2812629 100644
--- a/share/tmux.conf
+++ b/share/tmux.conf
@@ -8,7 +8,13 @@ set -s set-clipboard on                # tmux copy-mode -> OSC 52 -> browser cli
 set -s default-terminal "tmux-256color"
 set -s terminal-features[90] "xterm-256color:RGB"  # fixed index: re-sourcing must not append
 set -g history-limit 50000
-set -g mouse on                        # wheel scrolls history; Shift+drag selects natively
+set -g mouse on                        # wheel scrolls history; a drag selects in the browser (devdesk#51)
+# No right-click menus (devdesk#52): one stray click on them splits a pane or
+# kills a window (Claude's). Splits and kills stay on the keyboard (^b % ^b x).
+unbind -n MouseDown3Pane
+unbind -n M-MouseDown3Pane
+unbind -n MouseDown3Status
+unbind -n MouseDown3StatusLeft
 set -g allow-passthrough off       # output may not bypass tmux (title/clipboard spoofing)
 set -g renumber-windows on
 
diff --git a/tests/attach.bats b/tests/attach.bats
index 54d7e39..2ab8d05 100644
--- a/tests/attach.bats
+++ b/tests/attach.bats
@@ -1181,3 +1181,17 @@ JSONL
     [ "$(posts)" -eq 1 ]
     [ "$(cat "$DEVDESK_STATE_DIR/usage-warned")" = 2000018000 ]
 }
+
+@test "unsplit closes extra panes and keeps Claude's (#52)" {
+    start_server
+    devdesk new alpha
+    tmux -S "$DEVDESK_SOCKET" split-window -h -t =alpha:claude
+    tmux -S "$DEVDESK_SOCKET" split-window -v -t =alpha:shell
+    run devdesk attach --unsplit alpha
+    [ "$status" -eq 0 ]
+    [ "$(jq -r .closed <<<"$output")" = 2 ]
+    [ "$(tmux -S "$DEVDESK_SOCKET" list-panes -t =alpha:claude -F '#{pane_start_command}')" = "$REPO/libexec/devdesk-claude-run" ]
+    [ "$(tmux -S "$DEVDESK_SOCKET" list-panes -t =alpha:shell | wc -l)" = 1 ]
+    run devdesk attach --unsplit alpha
+    [ "$(jq -r .closed <<<"$output")" = 0 ]
+}
diff --git a/web/src/main.js b/web/src/main.js
index b15ae08..cc975cf 100644
--- a/web/src/main.js
+++ b/web/src/main.js
@@ -750,6 +750,16 @@ async function compact(session) {
   return undefined;
 }
 
+// A stray split (devdesk#52): close every extra pane, keeping Claude's.
+async function unsplit(session) {
+  try {
+    const result = await sessionAction('unsplit', session);
+    toast.success(result?.closed ? `Closed ${result.closed} pane${result.closed === 1 ? '' : 's'}` : 'No split panes');
+  } catch (error) {
+    toast.error(error.message);
+  }
+}
+
 async function copyLink() {
   const url = new URL(window.location.href);
   url.search = state.session ? `?arg=${encodeURIComponent(state.session)}` : '';
@@ -801,6 +811,7 @@ function buildCommands() {
     add({ id: 'win-shell', group: 'Terminal', icon: '1', label: 'Shell window', kbd: '^b 1', run: () => sendKeys('\x021') });
     add({ id: 'scroll', group: 'Terminal', icon: '⇞', label: 'Scroll back (tmux copy mode, q to leave)', kbd: '^b [', keywords: 'history scrollback', run: () => sendKeys('\x02[') });
     add({ id: 'detach', group: 'Terminal', icon: '⏏', label: 'Detach (the session keeps running)', kbd: '^b d', run: () => sendKeys('\x02d') });
+    add({ id: 'unsplit', group: 'Terminal', icon: '▣', label: 'Close split panes (keeps Claude)', keywords: 'pane split remove side by side layout', run: () => unsplit(state.session) });
   }
 
   if (state.session) {