diff --git a/regress/screen-redraw-cache.sh b/regress/screen-redraw-cache.sh
new file mode 100644
index 00000000..5f0a1ddf
--- /dev/null
+++ b/regress/screen-redraw-cache.sh
@@ -0,0 +1,147 @@
+#!/bin/sh
+
+# Exercise the scene caching in screen-redraw.c. A scene is built once and reused
+# until it is invalidated; redraw_get_scene rebuilds it when the window changes,
+# the generation number is bumped (panes moved/resized/swapped), or the offset
+# changes. These tests make such a change in place and capture afterwards: if the
+# matching invalidation did not fire, the stale cached scene would be drawn and
+# the capture would not match the golden.
+#
+# Each scene is rendered in an inner tmux attached inside an outer tmux pane. The
+# outer pane is captured and compared with a golden in screen-redraw-results/.
+#
+# Run with GENERATE=1 to (re)create the golden files.
+
+PATH=/bin:/usr/bin
+TERM=screen
+LC_ALL=C.UTF-8
+export TERM LC_ALL
+
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+TMUX="$TEST_TMUX -Ltest -f/dev/null"
+TMUX2="$TEST_TMUX -Ltest2 -f/dev/null"
+RESULTS=screen-redraw-results
+
+TMP=$(mktemp)
+trap "rm -f $TMP; $TMUX kill-server 2>/dev/null; $TMUX2 kill-server 2>/dev/null" \
+	0 1 15
+
+fail() {
+	echo "$*" >&2
+	exit 1
+}
+
+compare() {
+	sleep 1
+	$TMUX capturep -p >$TMP || exit 1
+	if [ -n "$GENERATE" ]; then
+		cp $TMP "$RESULTS/$1.result" || exit 1
+		echo "generated $1"
+	else
+		cmp -s $TMP "$RESULTS/$1.result" || \
+			fail "scene $1 differs from $RESULTS/$1.result"
+	fi
+}
+
+new_scene() {
+	$TMUX2 neww -d "sh -c 'exec sleep 100'" || exit 1
+	$TMUX2 selectw -t:\$ || exit 1
+	$TMUX2 resizew -x40 -y14 || exit 1
+}
+
+C="sh -c 'exec sleep 100'"
+
+$TMUX kill-server 2>/dev/null
+$TMUX2 kill-server 2>/dev/null
+
+$TMUX2 new -d -x40 -y14 "sh -c 'exec sleep 100'" || exit 1
+$TMUX2 set -g status off || exit 1
+$TMUX2 set -g window-size manual || exit 1
+
+$TMUX new -d -x40 -y14 || exit 1
+$TMUX set -g status off || exit 1
+$TMUX set -g window-size manual || exit 1
+$TMUX set -g default-terminal "tmux-256color" || exit 1
+$TMUX send -l "$TMUX2 attach" || exit 1
+$TMUX send Enter || exit 1
+sleep 1
+
+# --- Generation change: a pane is resized in place. ---
+
+# Two columns; first capture pins the initial divider position. The scene is
+# built here and cached.
+new_scene
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t0 || exit 1
+compare cache-resize-before
+
+# Move the divider left. resize-pane bumps the generation, so the cached scene
+# must be rebuilt and the divider must appear in its new position.
+$TMUX2 resize-pane -t0 -L 6 || exit 1
+compare cache-resize-after
+
+# --- Generation change: panes are swapped/rotated in place. ---
+
+# Three columns, each pane titled so the order is visible. The pane status line
+# makes a swap show up in the captured scene.
+new_scene
+$TMUX2 setw pane-border-format " #{pane_title} " || exit 1
+$TMUX2 setw pane-border-status top || exit 1
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t0 || exit 1
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t:.0 -T AAA || exit 1
+$TMUX2 selectp -t:.1 -T BBB || exit 1
+$TMUX2 selectp -t:.2 -T CCC || exit 1
+$TMUX2 selectp -t:.0 || exit 1
+compare cache-rotate-before
+
+# Rotate the panes; the titles must move with them in the rebuilt scene.
+# rotate-window keeps the cell geometry, so only its scene invalidation makes
+# this differ from cache-rotate-before.
+$TMUX2 rotate-window || exit 1
+$TMUX2 selectp -t:.0 || exit 1
+compare cache-rotate-after
+
+# --- Generation change: two panes swapped in place. ---
+
+# swap-pane likewise moves panes between cells without changing geometry; the
+# swapped titles must appear in the rebuilt scene.
+new_scene
+$TMUX2 setw pane-border-format " #{pane_title} " || exit 1
+$TMUX2 setw pane-border-status top || exit 1
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t:.0 -T LEFT || exit 1
+$TMUX2 selectp -t:.1 -T RIGHT || exit 1
+$TMUX2 selectp -t:.0 || exit 1
+compare cache-swap-before
+
+$TMUX2 swap-pane -d -s:.0 -t:.1 || exit 1
+$TMUX2 selectp -t:.0 || exit 1
+compare cache-swap-after
+
+# --- Window change: the client switches between two differently laid out
+# windows and back. The scene is keyed on the window, so each must show its own
+# layout and switching back must not show the other window's cached scene. ---
+
+# Window A: a single pane (no internal border).
+$TMUX2 neww -d "sh -c 'exec sleep 100'" || exit 1
+$TMUX2 selectw -t:\$ || exit 1
+$TMUX2 resizew -x40 -y14 || exit 1
+A=$($TMUX2 display -p '#{window_id}') || exit 1
+
+# Window B: a top/bottom split (a horizontal border).
+$TMUX2 neww -d "sh -c 'exec sleep 100'" || exit 1
+$TMUX2 selectw -t:\$ || exit 1
+$TMUX2 resizew -x40 -y14 || exit 1
+$TMUX2 splitw -v "$C" || exit 1
+B=$($TMUX2 display -p '#{window_id}') || exit 1
+
+$TMUX2 selectw -t$A || exit 1
+compare cache-window-a
+$TMUX2 selectw -t$B || exit 1
+compare cache-window-b
+$TMUX2 selectw -t$A || exit 1
+compare cache-window-a-again
+
+exit 0
diff --git a/regress/screen-redraw-floating.sh b/regress/screen-redraw-floating.sh
index c5b9d460..a60cdb40 100644
--- a/regress/screen-redraw-floating.sh
+++ b/regress/screen-redraw-floating.sh
@@ -95,6 +95,13 @@ $TMUX2 new-pane -x28 -y8 -X4 -Y1 -B double \
 	"sh -c 'printf FLOAT; exec sleep 100'" || exit 1
 compare floating-border-double
 
+# Floating pane with no border lines: redraw_mark_pane_borders returns early so
+# the float has no border at all, only its (clipped) content over the base pane.
+new_scene 40 12
+$TMUX2 new-pane -x20 -y6 -X10 -Y3 -B none \
+	"sh -c 'printf NOBORDER; exec sleep 100'" || exit 1
+compare floating-noborder
+
 # Floating pane positioned past the right and bottom edges: must clip.
 new_scene 40 12
 $TMUX2 new-pane -x20 -y6 -X30 -Y8 "sh -c 'printf CLIP; exec sleep 100'" || exit 1
diff --git a/regress/screen-redraw-indicators.sh b/regress/screen-redraw-indicators.sh
index f24ea400..60bf652b 100644
--- a/regress/screen-redraw-indicators.sh
+++ b/regress/screen-redraw-indicators.sh
@@ -125,6 +125,42 @@ $TMUX2 splitw -v "$C" || exit 1
 $TMUX2 selectp -t0 || exit 1
 compare two-pane-colour-horizontal -e
 
+# The colour split only applies with exactly two tiled panes. With three panes
+# the split is suppressed: the whole border uses the active pane's colour and
+# there is no coloured half (redraw_check_two_pane_colours returns 0).
+new_scene
+$TMUX2 setw pane-active-border-style fg=red || exit 1
+$TMUX2 setw pane-border-style fg=green || exit 1
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t0 || exit 1
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t0 || exit 1
+compare colour-three-suppressed -e
+
+# A floating pane is ignored by the two-pane count, so two tiled panes plus a
+# float still split. The float itself is never coloured by the indicator.
+new_scene
+$TMUX2 setw pane-active-border-style fg=red || exit 1
+$TMUX2 setw pane-border-style fg=green || exit 1
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t0 || exit 1
+$TMUX2 new-pane -x16 -y6 -X10 -Y2 "$C" || exit 1
+$TMUX2 selectp -t0 || exit 1
+compare colour-two-plus-float -e
+
+# --- Both indicators together. ---
+
+# pane-border-indicators both enables the arrow and the colour split at once
+# (it satisfies both the arrow and the colour branches). Two panes so the colour
+# split also applies.
+$TMUX2 set -g pane-border-indicators both || exit 1
+new_scene
+$TMUX2 setw pane-active-border-style fg=red || exit 1
+$TMUX2 setw pane-border-style fg=green || exit 1
+$TMUX2 splitw -h "$C" || exit 1
+$TMUX2 selectp -t0 || exit 1
+compare indicators-both -e
+
 # --- Marked pane. ---
 
 # A marked pane (select-pane -m) has its border drawn reversed. Captured with -e
diff --git a/regress/screen-redraw-results/cache-resize-after.result b/regress/screen-redraw-results/cache-resize-after.result
new file mode 100644
index 00000000..3153e9bc
--- /dev/null
+++ b/regress/screen-redraw-results/cache-resize-after.result
@@ -0,0 +1,14 @@
+              │
+              │
+              │
+              │
+              │
+              │
+              │
+              │
+              │
+              │
+              │
+              │
+              │
+              │
diff --git a/regress/screen-redraw-results/bidi-isolates.result b/regress/screen-redraw-results/cache-resize-before.result
similarity index 100%
rename from regress/screen-redraw-results/bidi-isolates.result
rename to regress/screen-redraw-results/cache-resize-before.result
diff --git a/regress/screen-redraw-results/cache-rotate-after.result b/regress/screen-redraw-results/cache-rotate-after.result
new file mode 100644
index 00000000..14f859e9
--- /dev/null
+++ b/regress/screen-redraw-results/cache-rotate-after.result
@@ -0,0 +1,14 @@
+── BBB ───┬── CCC ──┬── AAA ────────────
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
diff --git a/regress/screen-redraw-results/cache-rotate-before.result b/regress/screen-redraw-results/cache-rotate-before.result
new file mode 100644
index 00000000..95deb8e1
--- /dev/null
+++ b/regress/screen-redraw-results/cache-rotate-before.result
@@ -0,0 +1,14 @@
+── AAA ───┬── BBB ──┬── CCC ────────────
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
diff --git a/regress/screen-redraw-results/pane-status-mixed.result b/regress/screen-redraw-results/cache-swap-after.result
similarity index 76%
rename from regress/screen-redraw-results/pane-status-mixed.result
rename to regress/screen-redraw-results/cache-swap-after.result
index 7d8e1456..34e3b502 100644
--- a/regress/screen-redraw-results/pane-status-mixed.result
+++ b/regress/screen-redraw-results/cache-swap-after.result
@@ -1,4 +1,4 @@
-                    │
+── RIGHT ───────────┬── LEFT ───────────
                     │
                     │
                     │
diff --git a/regress/screen-redraw-results/cache-swap-before.result b/regress/screen-redraw-results/cache-swap-before.result
new file mode 100644
index 00000000..50aadd6d
--- /dev/null
+++ b/regress/screen-redraw-results/cache-swap-before.result
@@ -0,0 +1,14 @@
+── LEFT ────────────┬── RIGHT ──────────
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
diff --git a/regress/screen-redraw-results/cache-window-a-again.result b/regress/screen-redraw-results/cache-window-a-again.result
new file mode 100644
index 00000000..5cf5d3dc
--- /dev/null
+++ b/regress/screen-redraw-results/cache-window-a-again.result
@@ -0,0 +1,14 @@
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/regress/screen-redraw-results/cache-window-a.result b/regress/screen-redraw-results/cache-window-a.result
new file mode 100644
index 00000000..5cf5d3dc
--- /dev/null
+++ b/regress/screen-redraw-results/cache-window-a.result
@@ -0,0 +1,14 @@
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/regress/screen-redraw-results/cache-window-b.result b/regress/screen-redraw-results/cache-window-b.result
new file mode 100644
index 00000000..3a6144ae
--- /dev/null
+++ b/regress/screen-redraw-results/cache-window-b.result
@@ -0,0 +1,14 @@
+
+
+
+
+
+
+
+────────────────────────────────────────
+
+
+
+
+
+
diff --git a/regress/screen-redraw-results/colour-three-suppressed.result b/regress/screen-redraw-results/colour-three-suppressed.result
new file mode 100644
index 00000000..718cf036
--- /dev/null
+++ b/regress/screen-redraw-results/colour-three-suppressed.result
@@ -0,0 +1,12 @@
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
+          │         │
diff --git a/regress/screen-redraw-results/colour-two-plus-float.result b/regress/screen-redraw-results/colour-two-plus-float.result
new file mode 100644
index 00000000..74ea83e1
--- /dev/null
+++ b/regress/screen-redraw-results/colour-two-plus-float.result
@@ -0,0 +1,12 @@
+                    │
+         ┌────────────────┐
+         │                │
+         │                │
+         │                │
+         │                │
+         │                │
+         │                │
+         └────────────────┘
+                    │
+                    │
+                    │
diff --git a/regress/screen-redraw-results/floating-noborder.result b/regress/screen-redraw-results/floating-noborder.result
new file mode 100644
index 00000000..f15e2401
--- /dev/null
+++ b/regress/screen-redraw-results/floating-noborder.result
@@ -0,0 +1,12 @@
+base
+
+
+          NOBORDER
+
+
+
+
+
+
+
+
diff --git a/regress/screen-redraw-results/indicators-both.result b/regress/screen-redraw-results/indicators-both.result
new file mode 100644
index 00000000..4c9e76e7
--- /dev/null
+++ b/regress/screen-redraw-results/indicators-both.result
@@ -0,0 +1,12 @@
+                    │
+                    ←
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
+                    │
diff --git a/regress/screen-redraw-results/scrollbar-split-left.result b/regress/screen-redraw-results/scrollbar-split-left.result
new file mode 100644
index 00000000..8108a471
--- /dev/null
+++ b/regress/screen-redraw-results/scrollbar-split-left.result
@@ -0,0 +1,12 @@
+ base               │ base
+                    │ 
+                    │ 
+                    │ 
+                    │ 
+                    │ 
+                    │ 
+                    │ 
+                    │ 
+                    │ 
+                    │ 
+                    │ 
diff --git a/regress/screen-redraw-results/scrollbar-split-right.result b/regress/screen-redraw-results/scrollbar-split-right.result
new file mode 100644
index 00000000..b49abd2f
--- /dev/null
+++ b/regress/screen-redraw-results/scrollbar-split-right.result
@@ -0,0 +1,12 @@
+base                │base              
+                    │                  
+                    │                  
+                    │                  
+                    │                  
+                    │                  
+                    │                  
+                    │                  
+                    │                  
+                    │                  
+                    │                  
+                    │                  
diff --git a/regress/screen-redraw-scrollbars.sh b/regress/screen-redraw-scrollbars.sh
index aa44bfb8..926a4a11 100644
--- a/regress/screen-redraw-scrollbars.sh
+++ b/regress/screen-redraw-scrollbars.sh
@@ -106,6 +106,27 @@ $TMUX2 setw pane-scrollbars-style "bg=black,fg=white,width=1,pad=0" || exit 1
 $TMUX2 new-pane -x20 -y6 -X8 -Y3 "sh -c 'printf FLOAT; exec sleep 100'" || exit 1
 compare scrollbar-floating
 
+# Two tiled panes side by side, each with a right scrollbar. The left pane's
+# scrollbar sits between its content and the shared border, so the border is
+# extended outward over the scrollbar gap (the right += sb_w path in
+# redraw_mark_pane_borders) and must still join cleanly. The right pane's
+# scrollbar abuts the window edge.
+new_scene
+$TMUX2 setw pane-scrollbars-position right || exit 1
+$TMUX2 setw pane-scrollbars-style "bg=black,fg=white,width=1,pad=0" || exit 1
+$TMUX2 splitw -h "sh -c 'printf base; exec sleep 100'" || exit 1
+$TMUX2 selectp -t0 || exit 1
+compare scrollbar-split-right
+
+# Same split with the scrollbars on the left: the right pane's scrollbar now sits
+# between the shared border and its content (the left -= sb_w path).
+new_scene
+$TMUX2 setw pane-scrollbars-position left || exit 1
+$TMUX2 setw pane-scrollbars-style "bg=black,fg=white,width=1,pad=0" || exit 1
+$TMUX2 splitw -h "sh -c 'printf base; exec sleep 100'" || exit 1
+$TMUX2 selectp -t0 || exit 1
+compare scrollbar-split-left
+
 # Scrollbar slider in copy mode: with scrollback the slider is shorter than the
 # track, so this exercises the slider geometry (which only runs when the pane is
 # in a mode). copy-mode -H hides the position indicator, which is not stable.