diff --git a/screen-redraw.c b/screen-redraw.c
index a82d0566e..ea4af99bf 100644
--- a/screen-redraw.c
+++ b/screen-redraw.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: screen-redraw.c,v 1.154 2026/07/21 11:53:41 nicm Exp $ */
+/* $OpenBSD: screen-redraw.c,v 1.155 2026/07/21 13:27:41 nicm Exp $ */
 
 /*
  * Copyright (c) 2026 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -696,20 +696,22 @@ redraw_mark_pane_borders(struct redraw_build_ctx *bctx, struct window_pane *wp,
 	bottom = wp->yoff + wp->sy;
 
 	mark_left = (left >= 0);
-	mark_right = (right <= (int)bctx->w->sx);
 	mark_top = (top >= 0);
-	mark_bottom = (bottom <= (int)bctx->w->sy);
 
 	if (floating) {
+		mark_right = (right < (int)bctx->w->sx);
+		mark_bottom = (bottom < (int)bctx->w->sy);
 		if (left < 0)
 			left = 0;
-		if (right > (int)bctx->w->sx)
+		if (right >= (int)bctx->w->sx)
 			right = (int)bctx->w->sx - 1;
 		if (top < 0)
 			top = 0;
-		if (bottom > (int)bctx->w->sy)
+		if (bottom >= (int)bctx->w->sy)
 			bottom = (int)bctx->w->sy - 1;
 	} else {
+		mark_right = (right <= (int)bctx->w->sx);
+		mark_bottom = (bottom <= (int)bctx->w->sy);
 		if (pane_status == PANE_STATUS_TOP)
 			mark_bottom = 0;
 		else if (pane_status == PANE_STATUS_BOTTOM)