fix(text area): fix rendering with a multi-line placeholder

CHANGELOG.md

@@ -24,6 +24,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Fixed issue where Segments with a style of `None` aren't rendered https://github.com/Textualize/textual/pull/6109
 - Fixed visual glitches and crash when changing `DataTable.header_height` https://github.com/Textualize/textual/pull/6128
+- Fixed `TextArea` rendering with a multi-line `placeholder` https://github.com/Textualize/textual/issues/6122
 
 ## [6.1.0] - 2025-08-01
 

src/textual/widgets/_text_area.py

@@ -1176,6 +1176,15 @@ def _has_cursor(self) -> bool:
         """Is there a usable cursor?"""
         return not (self.read_only and not self.show_cursor)
 
+    @property
+    def _placeholder_lines(self) -> list[Content]:
+        content = (
+            Content(self.placeholder)
+            if isinstance(self.placeholder, str)
+            else self.placeholder
+        )
+        return content.split()
+
     def get_line(self, line_index: int) -> Text:
         """Retrieve the line at the given line index.
 
@@ -1206,15 +1215,11 @@ def render_line(self, y: int) -> Strip:
         Returns:
             A rendered line.
         """
-        if y == 0 and not self.text and self.placeholder:
+        if not self.text and self.placeholder and y < len(self._placeholder_lines):
             style = self.get_visual_style("text-area--placeholder")
-            content = (
-                Content(self.placeholder)
-                if isinstance(self.placeholder, str)
-                else self.placeholder
-            )
+            content = self._placeholder_lines[y]
             content = content.stylize(style)
-            if self._draw_cursor:
+            if y == 0 and self._draw_cursor:
                 theme = self._theme
                 cursor_style = theme.cursor_style if theme else None
                 if cursor_style: