Short-circuit text style parsing when unnecessary.

CHANGELOG.md

@@ -27,6 +27,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - The styles `scrollbar-background-active` and `scrollbar-color-hover` are no longer ignored https://github.com/Textualize/textual/pull/1480
 - The widget `Placeholder` can now have its width set to `auto` https://github.com/Textualize/textual/pull/1508
+- The style `text-style` option `none` can also be mixed with other options https://github.com/Textualize/textual/issues/1420
 
 ## [0.9.1] - 2022-12-30
 

src/textual/css/_style_properties.py

@@ -891,6 +891,7 @@ class StyleFlagsProperty:
         Raises:
             StyleValueError: If the value is an invalid style flag
         """
+        print(repr(style_flags))
         _rich_traceback_omit = True
         if style_flags is None:
             if obj.clear_rule(self.name):
@@ -909,7 +910,8 @@ class StyleFlagsProperty:
                             self.name, word, context="inline"
                         ),
                     )
-            style = Style.parse(style_flags)
+            # rich doesn't like "none" mixed with other styles, so short-circuit here.
+            style = Style() if "none" in words else Style.parse(style_flags)
             if obj.set_rule(self.name, style):
                 obj.refresh()