fix textarea scrollbar refresh

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Fixed `TextArea` cursor display on wrapped lines https://github.com/Textualize/textual/pull/6196
 - Fixed `remove_children` not refreshing layout https://github.com/Textualize/textual/pull/6206
 - Fixed flicker with :hover pseudo class https://github.com/Textualize/textual/pull/6214
+- Fixed scrollbar not updating after textarea paste https://github.com/Textualize/textual/pull/6219
 
 ### Added
 

src/textual/widgets/_text_area.py

@@ -1158,6 +1158,7 @@ def _refresh_size(self) -> None:
             # +1 width to make space for the cursor resting at the end of the line
             width, height = self.document.get_size(self.indent_width)
             self.virtual_size = Size(width + self.gutter_width + 1, height)
+        self._refresh_scrollbars()
 
     @property
     def _draw_cursor(self) -> bool:
@@ -1561,11 +1562,11 @@ def edit(self, edit: Edit) -> EditResult:
                 result.end_location,
             )
 
-        self._refresh_size()
         edit.after(self)
         self._build_highlight_map()
         self.post_message(self.Changed(self))
         self.update_suggestion()
+        self._refresh_size()
         return result
 
     def undo(self) -> None: