From 08a8a30ce903c6bd555a9cbe48a9e9b4638b3c32 Mon Sep 17 00:00:00 2001
From: Tristan Simas <tristan.simas@mail.mcgill.ca>
Date: Thu, 8 Oct 2026 00:03:49 -0400
Subject: [PATCH] Measure stream height at the assigned content width

---
 src/textual/layouts/stream.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/textual/layouts/stream.py b/src/textual/layouts/stream.py
index 49ac14e515..e70b4a253a 100644
--- a/src/textual/layouts/stream.py
+++ b/src/textual/layouts/stream.py
@@ -85,10 +85,13 @@ def arrange(
             margin = styles.margin
             gutter_width, gutter_height = styles.gutter.totals
             top, right, bottom, left = margin
+            child_width = width - (left + right)
             y += top if top > previous_margin else previous_margin
             previous_margin = bottom
             height = (
-                widget.get_content_height(size, viewport, width - gutter_width)
+                widget.get_content_height(
+                    size, viewport, max(0, child_width - gutter_width)
+                )
                 + gutter_height
             )
             if (max_height := styles.max_height) is not None and max_height.is_cells:
@@ -105,7 +108,7 @@ def arrange(
                 )
             placements.append(
                 _WidgetPlacement(
-                    _Region(left, y, width - (left + right), height),
+                    _Region(left, y, child_width, height),
                     null_offset,
                     margin,
                     widget,