Merge pull request #5936 from Textualize/keyline-glitch

Fix keyline glitch

Author: willmcgugan

CHANGELOG.md

@@ -17,6 +17,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Potential breaking change: Changed default `query_one` and `query_exactly_one` search to breadth first https://github.com/Textualize/textual/pull/5930
 - Cursor is now visible by default when in read only mode (restoring pre 3.6.0 behavior) https://github.com/Textualize/textual/pull/5934
 
+### Fixed
+
+- Fixed issue with Keylines not scrolling https://github.com/Textualize/textual/pull/5936
+
 ## [3.6.0] - 2025-07-06
 
 ### Fixed

src/textual/widget.py

@@ -4284,6 +4284,10 @@ def _check_refresh(self) -> None:
             else:
                 if self._scroll_required:
                     self._scroll_required = False
+                    if self.styles.keyline[0] != "none":
+                        # TODO: Feels like a hack
+                        # Perhaps there should be an explicit mechanism for backgrounds to refresh when scrolled?
+                        self._set_dirty()
                     screen.post_message(messages.UpdateScroll())
                 if self._repaint_required:
                     self._repaint_required = False