fix(panel): fix title missing panel background

Fix `Panel` title missing the panel background style.

This really just reverts the change in 7a38204. There's a history of
issues related to the panel title styles, so I was careful to run all
the examples in those issues to ensure there wasn't any regression.

Fixes #3569

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Fixed
+
+- Fixed `Panel` title missing the panel background style https://github.com/Textualize/rich/issues/3569
+
 ## [14.0.0] - 2025-03-30
 
 ### Added

rich/panel.py

@@ -146,8 +146,7 @@ class Panel(JupyterMixin):
             Padding(self.renderable, _padding) if any(_padding) else self.renderable
         )
         style = console.get_style(self.style)
-        partial_border_style = console.get_style(self.border_style)
-        border_style = style + partial_border_style
+        border_style = style + console.get_style(self.border_style)
         width = (
             options.max_width
             if self.width is None
@@ -206,7 +205,7 @@ class Panel(JupyterMixin):
 
         title_text = self._title
         if title_text is not None:
-            title_text.stylize_before(partial_border_style)
+            title_text.stylize_before(border_style)
 
         child_width = (
             width - 2
@@ -255,7 +254,7 @@ class Panel(JupyterMixin):
 
         subtitle_text = self._subtitle
         if subtitle_text is not None:
-            subtitle_text.stylize_before(partial_border_style)
+            subtitle_text.stylize_before(border_style)
 
         if subtitle_text is None or width <= 4:
             yield Segment(box.get_bottom([width - 2]), border_style)

tests/test_panel.py

@@ -148,6 +148,30 @@ def test_title_text_with_border_color() -> None:
     assert result == expected
 
 
+def test_title_text_with_panel_background() -> None:
+    """Regression test for https://github.com/Textualize/rich/issues/3569"""
+    panel = Panel(
+        "Hello, World",
+        style="on blue",
+        title=Text("title", style="red"),
+        subtitle=Text("subtitle", style="magenta bold"),
+    )
+    console = Console(
+        file=io.StringIO(),
+        width=50,
+        height=20,
+        legacy_windows=False,
+        force_terminal=True,
+        color_system="truecolor",
+    )
+    console.print(panel)
+
+    result = console.file.getvalue()
+    print(repr(result))
+    expected = "\x1b[44m╭─\x1b[0m\x1b[44m───────────────────\x1b[0m\x1b[31;44m title \x1b[0m\x1b[44m────────────────────\x1b[0m\x1b[44m─╮\x1b[0m\n\x1b[44m│\x1b[0m\x1b[44m \x1b[0m\x1b[44mHello, World\x1b[0m\x1b[44m                                  \x1b[0m\x1b[44m \x1b[0m\x1b[44m│\x1b[0m\n\x1b[44m╰─\x1b[0m\x1b[44m──────────────────\x1b[0m\x1b[1;35;44m subtitle \x1b[0m\x1b[44m──────────────────\x1b[0m\x1b[44m─╯\x1b[0m\n"
+    assert result == expected
+
+
 if __name__ == "__main__":
     expected = []
     for panel in tests: