diff --git a/.github/workflows/regress.yml b/.github/workflows/regress.yml
index b1e19e9e0..41f74f1c7 100644
--- a/.github/workflows/regress.yml
+++ b/.github/workflows/regress.yml
@@ -72,14 +72,14 @@ jobs:
 
       - name: build
         run: |
-         sh autogen.sh
+          sh autogen.sh
           ./configure ${{ matrix.configure }}
           ${{ matrix.make }} -j"$(getconf _NPROCESSORS_ONLN)"
 
       - name: test
         run: |
           cd regress
-          ${{ matrix.make }}
+          ${{ matrix.make }} -j"$(getconf _NPROCESSORS_ONLN)"
 
       - name: logs
         if: failure()
diff --git a/CHANGES b/CHANGES
index 62a7f8fc5..dcb26e1fc 100644
--- a/CHANGES
+++ b/CHANGES
@@ -10,8 +10,8 @@ CHANGES FROM 3.7c TO 3.8
   - modal panes may be created with new-pane -O; a window can have one modal
     pane and it prevents interaction with the other panes while it is active.
     -C closes the pane when the mouse is clicked outside it and -K sends all
-    keys, including the prefix key, to the pane. A modal pane is now used for
-    the editor in buffer mode;
+    keys, including the prefix key, to the pane. -D closes the modal pane with
+    Escape or C-c. A modal pane is now used for the editor in buffer mode;
 
   - new-pane -A creates a floating pane which remains above a zoomed pane;
     modal panes do this by default;
@@ -39,6 +39,9 @@ CHANGES FROM 3.7c TO 3.8
   The old format is still accepted; control mode clients receive old layouts
   unless they set the new-layouts flag.
 
+* Add remain-on-exit failed-key to keep a pane open after a failed command
+  until a key is pressed.
+
 * Add support for themes and improve default colours:
 
   - tmux now has builtin light and dark colour themes for terminals with 256 or
@@ -115,6 +118,12 @@ CHANGES FROM 3.7c TO 3.8
   in terminal-features, and add a utf8 feature for terminals which support
   UTF-8 output.
 
+* Add an appesc terminal feature for mintty's application escape key mode,
+  avoiding unsupported sequences on other terminals (Pete Dietl, issue 5626).
+
+* Preserve existing Ss and Se terminfo capabilities for cursor styles and
+  restoring the default cursor (issue 5476).
+
 * Add a #{A/count:frames} modifier to show a series of frames as an animation
   in the status line (issue 5412 from Fernando Daciuk).
 
@@ -189,10 +198,23 @@ CHANGES FROM 3.7c TO 3.8
   sent inside %begin/%end (issue 5458), do not let a stuck client prevent the
   server from exiting (issue 5444), and reset control mode offsets when a pane
   is respawned (issue 5498). Bound buffered command replies so a control mode
-  client that stops reading cannot consume unlimited memory (issue 5565).
+  client that stops reading cannot consume unlimited memory (issue 5565), and
+  fix a collision between the output discard and bracketed paste flags (issue
+  5622).
 
 * Fix grouped sessions sometimes being left as unusable command targets while
-  they are being killed (Bryce Miller, issue 5180).
+  they are being killed (Bryce Miller, issue 5180), and prevent reuse of a
+  session with no windows while detaching (Heon Jeong, issue 5620).
+
+* Free wait-for clients when they disconnect and do not run their remaining
+  queued commands (issue 5614).
+
+* Expand formats in run-shell -c like other start-directory flags (reported by
+  Saul Nogueras).
+
+* Fix session alert flag formats to check all windows (issue 5599).
+
+* Do not clear the marked pane when clicking on a pane border.
 
 * Fix choose mode filtering when more than one pane exists (issue 5326), and
   fix an infinite loop in customize mode when a filter does not match.
@@ -203,11 +225,18 @@ CHANGES FROM 3.7c TO 3.8
   status lines, menus, popups, wide characters and floating panes. This
   includes fixes for flicker with alternate screen applications and scrollbars
   (Michael Grant, issue 5351; Noam Stolero, issue 5350; Aung Myo Kyaw, issue
-  5098).
+  5098), and misplaced wrapped lines during partial redraws (Ben Maurer, issue
+  5625).
 
 * Do not crash looking for the next or previous session (issue 5344), or when
   no client is available.
 
+* Fix crashes when destroying a zoomed pane (Romain Francoise, issue 5591),
+  copying from a blank source pane (Kaixuan Li), or opening a mode prompt when
+  the client is offset into the window.
+
+* Avoid an infinite loop when assigning a width to WCHAR_MAX (issue 5602).
+
 CHANGES FROM 3.7b TO 3.7c
 
 * Build with jemalloc on macOS to avoid what appears to be a bug in calloc
diff --git a/regress/Makefile b/regress/Makefile
index 7a4387bd3..18518d274 100644
--- a/regress/Makefile
+++ b/regress/Makefile
@@ -1,33 +1,17 @@
 TESTS!= echo *.sh
 LOGDIR=logs
 
-.PHONY: all
-.NOTPARALLEL: all
+.PHONY: all prepare $(TESTS)
 
-all:
-	@mkdir -p "$(LOGDIR)"; \
-	rm -f "$(LOGDIR)"/*.log; \
-	failed=0; failures=; \
+all: prepare $(TESTS)
+	@failed=0; failures=; \
 	for test in $(TESTS); do \
 		base=$${test##*/}; \
 		log="$(LOGDIR)/$${base%.sh}.log"; \
-		rm -f "$$log"; \
-		printf '%-40s ' "$$test"; \
-		start=$$(date +%s); \
-		env -i LC_CTYPE=C.UTF-8 MallocNanoZone=0 \
-		    sh -x "$$test" >"$$log" 2>&1; \
-		if [ $$? -eq 0 ]; then \
-			end=$$(date +%s); \
-			rm -f "$$log"; \
-			echo "PASS ($$((end - start))s)"; \
-		else \
-			end=$$(date +%s); \
-			echo "FAIL ($$((end - start))s)"; \
-			echo " log: $$log"; \
+		if [ -f "$$log" ]; then \
 			failed=1; \
 			failures="$$failures $$test"; \
 		fi; \
-		sleep 1; \
 	done; \
 	if [ "$$failed" -ne 0 ]; then \
 		echo; \
@@ -39,3 +23,22 @@ all:
 		rmdir "$(LOGDIR)" 2>/dev/null || true; \
 	fi; \
 	exit $$failed
+
+prepare:
+	@mkdir -p "$(LOGDIR)"
+	@rm -f "$(LOGDIR)"/*.log
+
+$(TESTS): prepare
+	@base="$@"; base=$${base##*/}; \
+	log="$(LOGDIR)/$${base%.sh}.log"; \
+	start=$$(date +%s); \
+	if env -i LC_CTYPE=C.UTF-8 MallocNanoZone=0 \
+	    sh -x "$@" >"$$log" 2>&1; then \
+		end=$$(date +%s); \
+		rm -f "$$log"; \
+		printf '%-40s PASS (%ss)\n' "$@" "$$((end - start))"; \
+	else \
+		end=$$(date +%s); \
+		printf '%-40s FAIL (%ss)\n log: %s\n' \
+		    "$@" "$$((end - start))" "$$log"; \
+	fi
diff --git a/regress/control-client-exit-stalled.sh b/regress/control-client-exit-stalled.sh
index 431fd66d8..1574c821f 100644
--- a/regress/control-client-exit-stalled.sh
+++ b/regress/control-client-exit-stalled.sh
@@ -17,7 +17,7 @@ PATH=/bin:/usr/bin
 TERM=screen
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
-TMUX="$TEST_TMUX -Ltest"
+TMUX="$TEST_TMUX -Ltest$$"
 $TMUX kill-server 2>/dev/null
 
 DIR=$(mktemp -d)
diff --git a/regress/control-client-exit.sh b/regress/control-client-exit.sh
index ac08db5cc..d615dec48 100644
--- a/regress/control-client-exit.sh
+++ b/regress/control-client-exit.sh
@@ -19,7 +19,7 @@ PATH=/bin:/usr/bin
 TERM=screen
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
-TMUX="$TEST_TMUX -Ltest"
+TMUX="$TEST_TMUX -Ltest$$"
 $TMUX kill-server 2>/dev/null
 
 DIR=$(mktemp -d)
diff --git a/regress/control-client-run-shell-exit.sh b/regress/control-client-run-shell-exit.sh
index e8acc0419..e93dff20a 100644
--- a/regress/control-client-run-shell-exit.sh
+++ b/regress/control-client-run-shell-exit.sh
@@ -10,7 +10,7 @@ PATH=/bin:/usr/bin
 TERM=screen
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
-TMUX="$TEST_TMUX -Ltest"
+TMUX="$TEST_TMUX -Ltest$$"
 $TMUX kill-server 2>/dev/null
 
 OUT=$(mktemp)
diff --git a/regress/control-client-wait-exit.sh b/regress/control-client-wait-exit.sh
index 63739b284..26fe0ac76 100644
--- a/regress/control-client-wait-exit.sh
+++ b/regress/control-client-wait-exit.sh
@@ -10,7 +10,7 @@ PATH=/bin:/usr/bin
 TERM=screen
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
-TMUX="$TEST_TMUX -Ltest"
+TMUX="$TEST_TMUX -Ltest$$"
 $TMUX kill-server 2>/dev/null
 
 FIFO=$(mktemp -u)
diff --git a/regress/display-panes.sh b/regress/display-panes.sh
index 2d3faccd5..30c983c38 100644
--- a/regress/display-panes.sh
+++ b/regress/display-panes.sh
@@ -153,11 +153,13 @@ wait_format "$p0" '#{pane_in_mode}' '0'
 wait_option @picked "$p1"
 
 # Commands after display-panes run immediately while the mode remains.
+# Record the mode in the same command queue so client startup cannot race
+# the 500ms timeout.
 $TMUX set -g @after none || fail "set @after failed"
-$TMUX display-panes -Nd 500 -t "$p0" \; set -g @after fast ||
+$TMUX display-panes -Nd 500 -t "$p0" \; \
+    set -gF -t "$p0" @after '#{pane_mode}' ||
 	fail "display-panes immediate command failed"
-wait_option @after fast
-wait_format "$p0" '#{pane_mode}' 'panes-mode'
+wait_option @after 'panes-mode'
 wait_format "$p0" '#{pane_in_mode}' '0'
 
 # Existing zoom is restored on exit.
diff --git a/regress/format-fuzzy.sh b/regress/format-fuzzy.sh
index 00bc28bd4..e4cf3de15 100644
--- a/regress/format-fuzzy.sh
+++ b/regress/format-fuzzy.sh
@@ -7,6 +7,8 @@ TERM=screen
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
 TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+trap '$TMUX kill-server 2>/dev/null' 0
+trap 'exit 1' 1 2 15
 
 # test_format $format $expected_result
 test_format()
diff --git a/regress/format-modifiers.sh b/regress/format-modifiers.sh
index 58c02af7c..475feb524 100644
--- a/regress/format-modifiers.sh
+++ b/regress/format-modifiers.sh
@@ -18,6 +18,24 @@ export TZ LANG LC_ALL
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
 TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+FIFO1="${TMPDIR:-/tmp}/fmt-l-$$-1"
+FIFO2="${TMPDIR:-/tmp}/fmt-l-$$-2"
+HOLD1=
+HOLD2=
+CC1=
+CC2=
+
+cleanup()
+{
+	for pid in $HOLD1 $HOLD2 $CC1 $CC2; do
+		kill "$pid" 2>/dev/null
+		wait "$pid" 2>/dev/null
+	done
+	$TMUX kill-server 2>/dev/null
+	rm -f "$FIFO1" "$FIFO2"
+}
+trap cleanup 0
+trap 'exit 1' 1 2 15
 
 ESC=$(printf '\033')
 
@@ -579,8 +597,6 @@ assert_alive "verbose loop expansion"
 
 # L loops over attached clients.  Attach two control-mode clients, each held
 # open by a background process keeping a FIFO's write end open.
-FIFO1="${TMPDIR:-/tmp}/fmt-l-$$-1"
-FIFO2="${TMPDIR:-/tmp}/fmt-l-$$-2"
 rm -f "$FIFO1" "$FIFO2"
 mkfifo "$FIFO1" "$FIFO2" || exit 1
 # Hold the write ends open so the control clients stay attached.
@@ -605,9 +621,9 @@ test_format "#{L/nr:x}" "xx"
 test_format "#{L/r:x}" "xx"
 # Now detach one and confirm the count drops to one.
 kill $HOLD2 2>/dev/null
+wait $HOLD2 2>/dev/null
+HOLD2=
 sleep 1
 test_format "#{L:x}" "x"
-kill $HOLD1 $CC1 $CC2 2>/dev/null
-rm -f "$FIFO1" "$FIFO2"
 
 exit 0
diff --git a/regress/format-strings.sh b/regress/format-strings.sh
index 877e18fec..c06c340e3 100644
--- a/regress/format-strings.sh
+++ b/regress/format-strings.sh
@@ -7,6 +7,8 @@ TERM=screen
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
 TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+trap '$TMUX kill-server 2>/dev/null' 0
+trap 'exit 1' 1 2 15
 
 # test_format $format $expected_result
 test_format()
diff --git a/regress/hooks-lifecycle.sh b/regress/hooks-lifecycle.sh
index 3ec748ff4..8c8a41363 100644
--- a/regress/hooks-lifecycle.sh
+++ b/regress/hooks-lifecycle.sh
@@ -76,14 +76,14 @@ $TMUX set-hook -g session-closed \
 	fail "set-hook session-closed failed"
 
 # The only pane of the only window of a session exits: pane-exited, then
-# window-unlinked, then session-closed, each seeing the dead object in the
+# session-closed, then window-unlinked, each seeing the dead object in the
 # hook formats.
 pane=$($TMUX new -d -s doomed -n dwin -P -F '#{pane_id}' 'true') ||
 	fail "new-session doomed failed"
 wait_for @log \
-	"|pane-exited:$pane|window-unlinked:doomed:dwin|session-closed:doomed"
+	"|pane-exited:$pane|session-closed:doomed|window-unlinked:doomed:dwin"
 assert_unchanged @log \
-	"|pane-exited:$pane|window-unlinked:doomed:dwin|session-closed:doomed"
+	"|pane-exited:$pane|session-closed:doomed|window-unlinked:doomed:dwin"
 
 # The dead pane, window and session cannot be used as targets but the
 # server survives.
@@ -110,14 +110,14 @@ $TMUX set-hook -g pane-exited \
 	'set -gF @log "#{@log}|pane-exited:#{hook_pane}"' ||
 	fail "restore pane-exited hook failed"
 
-# kill-window on the last window: window-unlinked then session-closed but
+# kill-window on the last window: session-closed then window-unlinked but
 # no pane-exited for the panes in the killed window.
 $TMUX set -g @log '' || fail "reset @log failed"
 $TMUX new -d -s doomed2 -n dwin2 || fail "new-session doomed2 failed"
 $TMUX splitw -d -t doomed2:0 || fail "split-window doomed2 failed"
 $TMUX kill-window -t doomed2:0 || fail "kill-window failed"
-wait_for @log '|window-unlinked:doomed2:dwin2|session-closed:doomed2'
-assert_unchanged @log '|window-unlinked:doomed2:dwin2|session-closed:doomed2'
+wait_for @log '|session-closed:doomed2|window-unlinked:doomed2:dwin2'
+assert_unchanged @log '|session-closed:doomed2|window-unlinked:doomed2:dwin2'
 $TMUX has -t main || fail "server died after kill-window chain"
 
 # kill-session: session-closed fires first, then window-unlinked for its
diff --git a/regress/if-shell-error.sh b/regress/if-shell-error.sh
index 3b2dac753..968e0508c 100644
--- a/regress/if-shell-error.sh
+++ b/regress/if-shell-error.sh
@@ -12,7 +12,8 @@ $TMUX kill-server 2>/dev/null
 
 TMP=$(mktemp)
 OUT=$(mktemp)
-trap "rm -f $TMP $OUT" 0 1 15
+trap 'rm -f "$TMP" "$OUT"; $TMUX kill-server 2>/dev/null' 0
+trap 'exit 1' 1 2 15
 
 cat <<EOF >$TMP
 if 'true' 'wibble wobble'
diff --git a/regress/input-common.inc b/regress/input-common.inc
index ac04dbc24..a7ce572f6 100644
--- a/regress/input-common.inc
+++ b/regress/input-common.inc
@@ -4,6 +4,9 @@ TERM=screen
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
 TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
 
+# Keep panes alive until the next case or cleanup, without reading replies.
+INPUT_HOLD='while :; do sleep 3600; done'
+
 TMP=$(mktemp)
 EXP=$(mktemp)
 trap 'rm -f "$TMP" "$EXP"; $TMUX kill-server 2>/dev/null' 0 1 15
@@ -37,10 +40,10 @@ start_pane_hlimit()
 
 	$TMUX kill-server 2>/dev/null
 	sleep 0.1
-	$TMUX new-session -d -x 1 -y 1 -s test-setup "sleep 2" || exit 1
+	$TMUX new-session -d -x 1 -y 1 -s test-setup "$INPUT_HOLD" || exit 1
 	$TMUX set-option -g history-limit "$hlimit" || exit 1
 	$TMUX new-session -d -x "$sx" -y "$sy" -s "$name" \
-	    "printf '$seq'; sleep 2" || exit 1
+	    "printf '$seq'; $INPUT_HOLD" || exit 1
 	$TMUX kill-session -t test-setup
 	sleep 0.3
 }
diff --git a/regress/input-keys.sh b/regress/input-keys.sh
index cb771d19a..76dd5ea73 100644
--- a/regress/input-keys.sh
+++ b/regress/input-keys.sh
@@ -22,7 +22,19 @@ assert_key () {
 	      clear-history -t$W \; \
 	      send-keys -t$W "$key" 'EOL' || exit 1
 
-	actual_code=$($TMUX capturep -pt$W | \
+	# cat echoes the keys back asynchronously, so wait for the EOL marker
+	# to reach the pane instead of capturing straight away.
+	i=0
+	while [ $i -lt 50 ]; do
+		screen=$($TMUX capturep -pt$W)
+		case "$screen" in
+		*EOL*) break ;;
+		esac
+		i=$((i + 1))
+		sleep 0.1
+	done
+
+	actual_code=$(printf '%s\n' "$screen" | \
 			      head -1 | \
 			      sed -e 's/EOL.*$//')
 
diff --git a/regress/input-malformed.sh b/regress/input-malformed.sh
index 55a7e38c0..855af9f6c 100644
--- a/regress/input-malformed.sh
+++ b/regress/input-malformed.sh
@@ -2,6 +2,38 @@
 
 . ./input-common.inc
 
+# Wait for the terminator and following text to reach the parser.
+check_discard()
+{
+	name=$1
+	printf 'OK\n' >"$EXP"
+	i=0
+	while [ "$i" -lt 300 ]; do
+		capture_grid "$name" >"$TMP"
+		cmp -s "$TMP" "$EXP" && return 0
+		sleep 0.05
+		i=$((i + 1))
+	done
+	fail "$name (timed out waiting for discard)"
+}
+
+# The missing-terminator timer may expire before the string limit is reached
+# on a slow build. Clear any payload printed after the timeout, then check
+# that the string did not change the title and normal output has resumed.
+test_discard()
+{
+	name=$1
+	prefix=$2
+	start_cmd "$name" 8 3 "$INPUT_HOLD"
+	$TMUX select-pane -T discard-test || exit 1
+	$TMUX respawn-pane -k \
+	    "perl -e 'print qq{$prefix}, q{x} x 1100000, qq{\e\\\\\e[H\e[2JOK}'; $INPUT_HOLD" || exit 1
+	check_discard "$name"
+	$TMUX display-message -p -t "$name:" '#{pane_title}' >"$TMP" || exit 1
+	printf 'discard-test\n' >"$EXP"
+	cmp "$TMP" "$EXP" || fail "$name title"
+}
+
 start_cmd csi-param-discard 8 3 \
     "perl -e 'print qq{\e[}, q{1} x 80, qq{\030OK}'; sleep 2"
 check_capture csi-param-discard 'OK'
@@ -10,13 +42,8 @@ start_cmd csi-interm-discard 8 3 \
     "perl -e 'print qq{\e[    \030OK}'; sleep 2"
 check_capture csi-interm-discard 'OK'
 
-start_cmd osc-discard 8 3 \
-    "perl -e 'print qq{\e]2;}, q{x} x 1100000, qq{\e\\\\OK}'; sleep 2"
-check_capture osc-discard 'OK'
-
-start_cmd apc-discard 8 3 \
-    "perl -e 'print qq{\e_}, q{x} x 1100000, qq{\e\\\\OK}'; sleep 2"
-check_capture apc-discard 'OK'
+test_discard osc-discard '\e]2;'
+test_discard apc-discard '\e_'
 
 start_pane unknown-csi 8 3 '\033[?9999zOK'
 check_capture unknown-csi 'OK'
diff --git a/regress/input-scroll.sh b/regress/input-scroll.sh
index 6ae48e96d..206c4db95 100644
--- a/regress/input-scroll.sh
+++ b/regress/input-scroll.sh
@@ -51,7 +51,7 @@ $TMUX kill-server 2>/dev/null
 sleep 0.1
 $TMUX new-session -d -x 5 -y 3 -s history \; \
     set-option -g history-limit 3 \; \
-    respawn-pane -k "printf '01\n02\n03\n04\n05\n06'; sleep 2" || exit 1
+    respawn-pane -k "printf '01\n02\n03\n04\n05\n06'; $INPUT_HOLD" || exit 1
 sleep 0.3
 $TMUX capture-pane -pN -t history: -S - -E - | normalize_capture >"$TMP"
 printf "%s\n" '01
diff --git a/regress/respawn-pane-control-lag.sh b/regress/respawn-pane-control-lag.sh
index b71ce1946..8ca8146ed 100644
--- a/regress/respawn-pane-control-lag.sh
+++ b/regress/respawn-pane-control-lag.sh
@@ -15,7 +15,7 @@ PATH=/bin:/usr/bin
 TERM=screen
 
 [ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
-TMUX="$TEST_TMUX -Ltest"
+TMUX="$TEST_TMUX -Ltest$$"
 $TMUX kill-server 2>/dev/null
 
 DIR=$(mktemp -d)
diff --git a/regress/run-shell-cwd.sh b/regress/run-shell-cwd.sh
index abcc89ee6..0371a43df 100644
--- a/regress/run-shell-cwd.sh
+++ b/regress/run-shell-cwd.sh
@@ -22,14 +22,26 @@ check_directory()
 	fi
 }
 
-# Expand the current pane's directory in the same command queue as creation.
+# The start path is available immediately, before the child is scheduled.
+# Use it to test the format context in the same command queue as creation.
 $TMUX new-session -d -s test -c "$TMP/first" 'sleep 60' \; \
-	 run-shell -c '#{pane_current_path}' "pwd >'$TMP/out'" || exit 1
+	 run-shell -c '#{pane_start_path}' "pwd >'$TMP/out'" || exit 1
 check_directory "$TMP/first"
 
 # An explicit target must supply the format context, including with a delay.
 pane=$($TMUX new-window -d -P -F '#{pane_id}' -t test \
 	-c "$TMP/second dir" 'sleep 60') || exit 1
+# The current path depends on the operating system finding the child process.
+i=0
+while [ "$($TMUX display-message -p -t "$pane" '#{pane_current_path}')" != \
+    "$TMP/second dir" ]; do
+	if [ "$i" -ge 100 ]; then
+		echo "Timed out waiting for pane current directory"
+		exit 1
+	fi
+	sleep 0.05
+	i=$((i + 1))
+done
 $TMUX run-shell -t "$pane" -d 0.1 -c '#{pane_current_path}' \
 	"pwd >'$TMP/out'" || exit 1
 check_directory "$TMP/second dir"
diff --git a/regress/screen-redraw-tiled.sh b/regress/screen-redraw-tiled.sh
index de7c57aff..809b4d4c4 100644
--- a/regress/screen-redraw-tiled.sh
+++ b/regress/screen-redraw-tiled.sh
@@ -95,7 +95,8 @@ layout_tee_down() {		# top/bottom, bottom split: a top tee
 $TMUX kill-server 2>/dev/null
 $TMUX2 kill-server 2>/dev/null
 
-$TMUX2 new -d -x40 -y14 "sh -c 'exec sleep 100'" || exit 1
+# Keep the anchor window alive until cleanup, even on slow test runs.
+$TMUX2 new -d -x40 -y14 'exec cat' || exit 1
 $TMUX2 set -g status off || exit 1
 $TMUX2 set -g window-size manual || exit 1
 $TMUX2 set -g pane-border-format " #{pane_index} " || exit 1
diff --git a/regress/tty-keys.sh b/regress/tty-keys.sh
index 0a3ef318c..914c15c84 100644
--- a/regress/tty-keys.sh
+++ b/regress/tty-keys.sh
@@ -9,14 +9,37 @@ $TMUX kill-server 2>/dev/null
 TMUX2="$TEST_TMUX -LtestB$$ -f/dev/null"
 $TMUX2 kill-server 2>/dev/null
 
-TMP=$(mktemp)
-trap "rm -f $TMP" 0 1 15
+TMP=$(mktemp) || exit 1
+prompt_pid=
+
+cleanup () {
+	if [ -n "$prompt_pid" ]; then
+		kill "$prompt_pid" 2>/dev/null
+		wait "$prompt_pid" 2>/dev/null
+	fi
+	$TMUX kill-server 2>/dev/null
+	$TMUX2 kill-server 2>/dev/null
+	rm -f "$TMP"
+}
+trap cleanup 0
+trap 'exit 1' 1 2 15
+
+fail () {
+	echo "[FAIL] $*" >&2
+	exit 1
+}
 
 $TMUX2 -f/dev/null new -d || exit 1
 $TMUX -f/dev/null new -d "$TMUX2 attach" || exit 1
-sleep 1
+i=0
+while [ -z "$($TMUX2 list-clients -F '#{client_name}')" ]; do
+	[ "$i" -lt 100 ] || fail "inner client did not attach"
+	sleep 0.05
+	i=$((i + 1))
+done
 
 exit_status=0
+assertion=0
 
 format_string () {
 	case $1 in
@@ -34,12 +57,33 @@ assert_key () {
 	expected_name=$2
 	format_string=$(format_string "$expected_name")
 
-	$TMUX2 command-prompt -k 'display-message -pl '"$format_string" > "$TMP" &
-	sleep 0.05
+	# Use a different prompt each time so a stale redraw cannot look ready.
+	assertion=$((assertion + 1))
+	prompt="tty-keys-$assertion:"
+	$TMUX2 command-prompt -k -p "$prompt" \
+	    'display-message -pl '"$format_string" > "$TMP" &
+	prompt_pid=$!
+	i=0
+	while ! $TMUX capture-pane -p | grep -Fq "$prompt"; do
+		kill -0 "$prompt_pid" 2>/dev/null || \
+		    fail "$keys -> $expected_name: prompt exited before becoming ready"
+		[ "$i" -lt 100 ] || \
+		    fail "$keys -> $expected_name: timed out waiting for prompt"
+		sleep 0.05
+		i=$((i + 1))
+	done
 
-	$TMUX send-keys $keys
+	$TMUX send-keys $keys || fail "could not send $keys"
 
-	wait
+	i=0
+	while kill -0 "$prompt_pid" 2>/dev/null; do
+		[ "$i" -lt 100 ] || \
+		    fail "$keys -> $expected_name: timed out waiting for key"
+		sleep 0.05
+		i=$((i + 1))
+	done
+	wait "$prompt_pid" || fail "$keys -> $expected_name: prompt failed"
+	prompt_pid=
 
 	keys=$(printf '%s' "$keys" | sed -e 's/Escape/\\\\033/g' | tr -d '[:space:]')
 	actual_name=$(tr -d '[:space:]' < "$TMP")
@@ -365,7 +409,4 @@ assert_key 'Escape [32;2u' 'S-Space'
 assert_key 'Escape [9;5u' 'C-Tab'
 assert_key 'Escape [1;5Z' 'C-S-Tab'
 
-$TMUX kill-server 2>/dev/null
-$TMUX2 kill-server 2>/dev/null
-
 exit $exit_status