diff --git a/regress/floating-pane-zoom.sh b/regress/floating-pane-zoom.sh
new file mode 100644
index 000000000..84e9db00c
--- /dev/null
+++ b/regress/floating-pane-zoom.sh
@@ -0,0 +1,158 @@
+#!/bin/sh
+
+# Moving, resizing and reordering an over-zoom float must leave the tiled
+# pane zoomed, and the changes must survive an explicit unzoom.
+
+PATH=/bin:/usr/bin
+TERM=screen
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -LtestA$$ -f/dev/null"
+trap '$TMUX kill-server 2>/dev/null' 0
+trap 'exit 1' 1 2 15
+
+fail()
+{
+	echo "$*" >&2
+	exit 1
+}
+
+run()
+{
+	$TMUX "$@" || fail "failed: $*"
+}
+
+check()
+{
+	got=$(run display-message -p -t "$1" "$2") || exit 1
+	[ "$got" = "$3" ] || fail "$1 $2: got '$got', expected '$3'"
+}
+
+check_zoom()
+{
+	check "$base" '#{window_zoomed_flag}:#{pane_zoomed_flag}' '1:1'
+	check "$float" '#{pane_floating_flag}:#{pane_active}' "1:$active"
+	check "$base" '#{@unzoomed}' ''
+}
+
+run new-session -d -x 80 -y 24
+base=$(run display-message -p '#{pane_id}') || exit 1
+other=$(run split-window -dPF '#{pane_id}') || exit 1
+layout=$(run display-message -p '#{window_layout}') || exit 1
+run set-hook -g window-unzoomed 'set -g @unzoomed 1'
+
+# Cover creation before and after zoom, with both the float and the tiled
+# pane active. Modal panes use the same over-zoom flag.
+for mode in before after detached modal; do
+	if [ "$mode" != before ]; then
+		run resize-pane -Z -t "$base"
+	fi
+	case "$mode" in
+	detached) flags=-Ad; active=0 ;;
+	modal) flags=-O; active=1 ;;
+	*) flags=-A; active=1 ;;
+	esac
+	float=$(run new-pane "$flags" -PF '#{pane_id}' -t "$base" \
+	    -x 20 -y 8 -X 8 -Y 3 '') || exit 1
+	if [ "$mode" = before ]; then
+		run resize-pane -Z -t "$base"
+	fi
+	run set -gu @unzoomed
+	check_zoom
+
+	run move-pane -t "$float" -D
+	check "$float" '#{pane_top}' 5
+	check_zoom
+	run move-pane -t "$float" -U 2 -R 3 -L 1
+	check "$float" '#{pane_left}:#{pane_top}' '11:3'
+	check_zoom
+	run move-pane -t "$float" -X 25% -Y 25%
+	check "$float" '#{pane_left}:#{pane_top}' '21:7'
+	check_zoom
+	run move-pane -t "$float" -P bottom-right
+	check "$float" '#{pane_left}:#{pane_top}' '61:17'
+	check_zoom
+	run resize-pane -t "$float" -x 30 -y 10
+	check "$float" '#{pane_width}:#{pane_height}' '28:8'
+	check_zoom
+	run resize-pane -t "$float" -U 1 -L 2
+	check "$float" '#{pane_left}:#{pane_top}:#{pane_width}:#{pane_height}' \
+	    '59:16:30:9'
+	check_zoom
+	run move-pane -t "$float" -P centre
+	check "$float" '#{pane_left}:#{pane_top}' '25:7'
+	check_zoom
+
+	# Failed commands must not change zoom either.
+	for command in 'move-pane -D invalid' 'move-pane -P invalid' \
+	    'move-pane -z invalid' 'resize-pane -x invalid' \
+	    'resize-pane -D invalid'; do
+		$TMUX $command -t "$float" 2>/dev/null &&
+		    fail "unexpected success: $command"
+		check_zoom
+	done
+
+	run resize-pane -Z -t "$base"
+	check "$float" '#{pane_left}:#{pane_top}:#{pane_width}:#{pane_height}' \
+	    '25:7:30:9'
+	run kill-pane -t "$float"
+	check "$base" '#{window_layout}' "$layout"
+done
+
+# Put an ordinary (hidden while zoomed) float between two over-zoom floats
+# in the stacking order. Reordering must skip it when counting visible
+# positions, but keep all floats ahead of the tiled panes after unzoom.
+back=$(run new-pane -AdPF '#{pane_id}' -t "$base" '') || exit 1
+hidden=$(run new-pane -dPF '#{pane_id}' -t "$base" '') || exit 1
+float=$(run new-pane -AdPF '#{pane_id}' -t "$base" '') || exit 1
+active=0
+run resize-pane -Z -t "$base"
+run set -gu @unzoomed
+
+for position in backward back forward-loop; do
+	run move-pane -t "$float" -P front
+	run move-pane -t "$float" -P "$position"
+	check "$float" '#{pane_z}' 1
+	check "$back" '#{pane_z}' 0
+	check_zoom
+done
+for position in forward front backward-loop; do
+	run move-pane -t "$float" -P back
+	run move-pane -t "$float" -P "$position"
+	check "$float" '#{pane_z}' 0
+	check "$back" '#{pane_z}' 1
+	check_zoom
+done
+for z in 1 0 99; do
+	run move-pane -t "$float" -z "$z"
+	want=$z
+	[ "$z" = 99 ] && want=1
+	check "$float" '#{pane_z}' "$want"
+	check_zoom
+done
+run resize-pane -Z -t "$base"
+check "$float" '#{pane_z}' 2
+check "$base" '#{pane_z}' 4
+run kill-pane -t "$hidden"
+run kill-pane -t "$back"
+
+# Explicit zoom toggling and operations on tiled panes retain their
+# existing behaviour. The over-zoom flag alone does not make a pane a float:
+# zooming the float itself gives it a tiled cell until unzoom.
+run resize-pane -Z -t "$float"
+check "$float" '#{pane_zoomed_flag}:#{pane_floating_flag}' '1:0'
+run resize-pane -t "$float" -x 25
+check "$float" '#{window_zoomed_flag}:#{pane_floating_flag}:#{pane_width}' \
+    '0:1:23'
+run resize-pane -Z -t "$base"
+run resize-pane -t "$other" -D 1
+check "$base" '#{window_zoomed_flag}' 0
+
+# A hidden ordinary float must still be unzoomed before resizing it.
+hidden=$(run new-pane -dPF '#{pane_id}' -t "$base" '') || exit 1
+run resize-pane -Z -t "$base"
+run resize-pane -t "$hidden" -x 25
+check "$hidden" '#{window_zoomed_flag}:#{pane_floating_flag}:#{pane_width}' \
+    '0:1:23'
+
+exit 0