style and components fixes

docs/examples/widgets/option_list_options.py

@@ -1,6 +1,6 @@
 from textual.app import App, ComposeResult
 from textual.widgets import Footer, Header, OptionList
-from textual.widgets.option_list import Option, Separator
+from textual.widgets.option_list import Option
 
 
 class OptionListApp(App[None]):
@@ -11,22 +11,22 @@ class OptionListApp(App[None]):
         yield OptionList(
             Option("Aerilon", id="aer"),
             Option("Aquaria", id="aqu"),
-            Separator(),
+            None,
             Option("Canceron", id="can"),
             Option("Caprica", id="cap", disabled=True),
-            Separator(),
+            None,
             Option("Gemenon", id="gem"),
-            Separator(),
+            None,
             Option("Leonis", id="leo"),
             Option("Libran", id="lib"),
-            Separator(),
+            None,
             Option("Picon", id="pic"),
-            Separator(),
+            None,
             Option("Sagittaron", id="sag"),
             Option("Scorpia", id="sco"),
-            Separator(),
+            None,
             Option("Tauron", id="tau"),
-            Separator(),
+            None,
             Option("Virgon", id="vir"),
         )
         yield Footer()

src/textual/command.py

@@ -35,7 +35,6 @@ from typing import (
 
 import rich.repr
 from rich.align import Align
-from rich.style import Style
 from rich.text import Text
 from typing_extensions import Final, TypeAlias
 
@@ -48,7 +47,7 @@ from textual.fuzzy import Matcher
 from textual.message import Message
 from textual.reactive import var
 from textual.screen import Screen, SystemModalScreen
-from textual.style import Style as VisualStyle
+from textual.style import Style
 from textual.timer import Timer
 from textual.types import IgnoreReturnCallbackType
 from textual.visual import VisualType
@@ -190,6 +189,10 @@ class Provider(ABC):
         Args:
             screen: A reference to the active screen.
         """
+        if match_style is not None:
+            assert isinstance(
+                match_style, Style
+            ), "match_style must be a Visual style if given"
         self.__screen = screen
         self.__match_style = match_style
         self._init_task: Task | None = None
@@ -228,8 +231,13 @@ class Provider(ABC):
         Returns:
             A [fuzzy matcher][textual.fuzzy.Matcher] object for matching against candidate hits.
         """
+        match_style = self.match_style
+        # match_style = Style(bold=True, underline=True)
+
         return Matcher(
-            user_input, match_style=self.match_style, case_sensitive=case_sensitive
+            user_input,
+            match_style=match_style,
+            case_sensitive=case_sensitive,
         )
 
     def _post_init(self) -> None:
@@ -806,9 +814,7 @@ class CommandPalette(SystemModalScreen[None]):
         self.app.post_message(CommandPalette.Opened())
         self._calling_screen = self.app.screen_stack[-2]
 
-        match_style = self.get_component_rich_style(
-            "command-palette--highlight", partial=True
-        )
+        match_style = self.get_visual_style("command-palette--highlight", partial=True)
 
         assert self._calling_screen is not None
         self._providers = [
@@ -1108,9 +1114,10 @@ class CommandPalette(SystemModalScreen[None]):
                     yield Content.from_rich_text(hit.prompt)
                 else:
                     yield Content.from_markup(hit.prompt)
+
                 # Optional help text
                 if hit.help:
-                    help_style = VisualStyle.from_styles(
+                    help_style = Style.from_styles(
                         self.get_component_styles("command-palette--help-text")
                     )
                     yield Content.from_markup(hit.help).stylize_before(help_style)

src/textual/content.py

@@ -948,7 +948,7 @@ class Content(Visual):
         self,
         base_style: Style = Style.null(),
         end: str = "\n",
-        parse_style: Callable[[str], Style] | None = None,
+        parse_style: Callable[[str | Style], Style] | None = None,
     ) -> Iterable[tuple[str, Style]]:
         """Render Content in to an iterable of strings and styles.
 
@@ -971,11 +971,13 @@ class Content(Visual):
                 yield end, base_style
             return
 
-        get_style: Callable[[str], Style]
+        get_style: Callable[[str | Style], Style]
         if parse_style is None:
 
-            def get_style(style: str, /) -> Style:
+            def get_style(style: str | Style) -> Style:
                 """The default get_style method."""
+                if isinstance(style, Style):
+                    return style
                 try:
                     visual_style = Style.parse(style)
                 except Exception:

src/textual/css/stylesheet.py

@@ -220,7 +220,7 @@ class Stylesheet:
         self._parse_cache.clear()
         self._style_parse_cache.clear()
 
-    def parse_style(self, style_text: str) -> Style:
+    def parse_style(self, style_text: str | Style) -> Style:
         """Parse a (visual) Style.
 
         Args:
@@ -229,6 +229,8 @@ class Stylesheet:
         Returns:
             New Style instance.
         """
+        if isinstance(style_text, Style):
+            return style_text
         if style_text in self._style_parse_cache:
             return self._style_parse_cache[style_text]
         style = parse_style(style_text)

src/textual/fuzzy.py

@@ -12,8 +12,9 @@ from re import IGNORECASE, escape, finditer, search
 from typing import Iterable, NamedTuple
 
 import rich.repr
-from rich.style import Style
-from rich.text import Text
+
+from textual.content import Content
+from textual.visual import Style
 
 
 class _Search(NamedTuple):
@@ -203,7 +204,7 @@ class Matcher:
         """
         return self.fuzzy_search.match(self.query, candidate)[0]
 
-    def highlight(self, candidate: str) -> Text:
+    def highlight(self, candidate: str) -> Content:
         """Highlight the candidate with the fuzzy match.
 
         Args:
@@ -212,11 +213,11 @@ class Matcher:
         Returns:
             A [rich.text.Text][`Text`] object with highlighted matches.
         """
-        text = Text.from_markup(candidate)
+        content = Content.from_markup(candidate)
         score, offsets = self.fuzzy_search.match(self.query, candidate)
         if not score:
-            return text
+            return content
         for offset in offsets:
             if not candidate[offset].isspace():
-                text.stylize(self._match_style, offset, offset + 1)
-        return text
+                content = content.stylize(self._match_style, offset, offset + 1)
+        return content

src/textual/style.py

@@ -177,10 +177,14 @@ class Style:
             new_style = Style(
                 (
                     other.background
-                    if self.background is None
+                    if (self.background is None or self.background.a == 0)
                     else self.background + other.background
                 ),
-                self.foreground if other.foreground is None else other.foreground,
+                (
+                    self.foreground
+                    if (other.foreground is None or other.foreground.a == 0)
+                    else other.foreground
+                ),
                 self.bold if other.bold is None else other.bold,
                 self.dim if other.dim is None else other.dim,
                 self.italic if other.italic is None else other.italic,
@@ -368,6 +372,7 @@ class Style:
             bold=self.bold,
             dim=self.dim,
             italic=self.italic,
+            underline=self.underline,
             reverse=self.reverse,
             strike=self.strike,
             link=self.link,

src/textual/widget.py

@@ -1044,17 +1044,20 @@ class Widget(DOMNode):
 
         return partial_style if partial else style
 
-    def get_visual_style(self, *component_classes: str) -> VisualStyle:
+    def get_visual_style(
+        self, *component_classes: str, partial: bool = False
+    ) -> VisualStyle:
         """Get the visual style for the widget, including any component styles.
 
         Args:
             component_classes: Optional component styles.
+            partial: Return a partial style (not combined with parent).
 
         Returns:
             A Visual style instance.
 
         """
-        cache_key = (self._pseudo_classes_cache_key, component_classes)
+        cache_key = (self._pseudo_classes_cache_key, component_classes, partial)
         if (visual_style := self._visual_style_cache.get(cache_key, None)) is None:
             background = Color(0, 0, 0, 0)
             color = Color(255, 255, 255, 0)
@@ -1064,6 +1067,9 @@ class Widget(DOMNode):
 
             def iter_styles() -> Iterable[StylesBase]:
                 """Iterate over the styles from the DOM and additional components styles."""
+                if partial:
+                    node = self
+                else:
                     for node in reversed(self.ancestors_with_self):
                         yield node.styles
                 for name in component_classes:
@@ -4221,7 +4227,7 @@ class Widget(DOMNode):
         """
         self.app.capture_mouse(None)
 
-    def select_all(self) -> None:
+    def text_select_all(self) -> None:
         """Select the entire widget."""
         self.screen._select_all_in_widget(self)
 
@@ -4286,9 +4292,9 @@ class Widget(DOMNode):
     async def _on_click(self, event: events.Click) -> None:
         if event.widget is self:
             if event.chain == 2:
-                self.select_all()
+                self.text_select_all()
             elif event.chain == 3 and self.parent is not None:
-                self.select_container.select_all()
+                self.select_container.text_select_all()
 
         await self.broker_event("click", event)
 

src/textual/widgets/_option_list.py

@@ -11,7 +11,7 @@ from textual._loop import loop_last
 from textual.binding import Binding, BindingType
 from textual.cache import LRUCache
 from textual.css.styles import RulesMap
-from textual.geometry import Region, Size
+from textual.geometry import Region, Size, clamp
 from textual.message import Message
 from textual.reactive import reactive
 from textual.scroll_view import ScrollView
@@ -57,7 +57,7 @@ class Option:
         self._prompt = prompt
         self._visual: Visual | None = None
         self._id = id
-        self._disabled = disabled
+        self.disabled = disabled
         self._divider = False
 
     @property
@@ -70,9 +70,15 @@ class Option:
         """Optional ID for the option."""
         return self._id
 
-    @property
-    def disabled(self) -> bool:
-        return self._disabled
+    def _set_prompt(self, prompt: VisualType) -> None:
+        """Update the prompt.
+
+        Args:
+            prompt: New prompt.
+
+        """
+        self._prompt = prompt
+        self._visual = None
 
     def __hash__(self) -> int:
         return id(self)
@@ -180,7 +186,7 @@ class OptionList(ScrollView, can_focus=True):
     highlighted: reactive[int | None] = reactive(None)
     """The index of the currently-highlighted option, or `None` if no option is highlighted."""
 
-    hover_option_index: reactive[int | None] = reactive(None)
+    _mouse_hovering_over: reactive[int | None] = reactive(None)
     """The index of the option under the mouse or `None`."""
 
     class OptionMessage(Message):
@@ -247,14 +253,12 @@ class OptionList(ScrollView, can_focus=True):
         tooltip: VisualType | None = None,
     ):
         super().__init__(name=name, id=id, classes=classes, disabled=disabled)
-        self._option_id = 0
         self._wrap = wrap
         self._markup = markup
         self._options: list[Option] = []
         self._id_to_option: dict[str, Option] = {}
         self._option_to_index: dict[Option, int] = {}
 
-        self._visuals: dict[int, Visual] = {}
         self._option_render_cache: LRUCache[tuple[Option, Style], list[Strip]]
         self._option_render_cache = LRUCache(maxsize=1024)
 
@@ -264,6 +268,9 @@ class OptionList(ScrollView, can_focus=True):
             self.tooltip = tooltip
 
         self.add_options(content)
+        if self._options:
+            # TODO: Inherited from previous version. Do we always want this?
+            self.action_first()
 
     @property
     def options(self) -> Sequence[Option]:
@@ -285,8 +292,11 @@ class OptionList(ScrollView, can_focus=True):
         Returns:
             The `OptionList` instance.
         """
+        self._options.clear()
         self._line_cache.clear()
         self._option_render_cache.clear()
+        self._id_to_option.clear()
+        self._option_to_index.clear()
         self.highlighted = None
         self.refresh()
         return self
@@ -298,6 +308,16 @@ class OptionList(ScrollView, can_focus=True):
             new_options: Content of new options.
         """
 
+        option_ids = [
+            option._id
+            for option in new_options
+            if isinstance(option, Option) and option._id is not None
+        ]
+        if len(option_ids) != len(set(option_ids)):
+            raise DuplicateID(
+                "New options contain duplicated IDs; Ensure that the IDs are unique."
+            )
+
         options = self._options
         add_option = self._options.append
         for prompt in new_options:
@@ -309,17 +329,15 @@ class OptionList(ScrollView, can_focus=True):
                 continue
             else:
                 option = Option(prompt)
-            hash(option)
             self._option_to_index[option] = len(options)
-            add_option(option)
             if option._id is not None:
                 if option._id in self._id_to_option:
-                    raise DuplicateID("Unable to add {option!r} due to duplicate ID")
+                    raise DuplicateID(f"Unable to add {option!r} due to duplicate ID")
                 self._id_to_option[option._id] = option
-
+            add_option(option)
         return self
 
-    def add_option(self, option: Option | VisualType | None) -> Self:
+    def add_option(self, option: Option | VisualType | None = None) -> Self:
         """Add a new option to the end of the option list.
 
         Args:
@@ -397,7 +415,7 @@ class OptionList(ScrollView, can_focus=True):
         Returns:
             The `OptionList` instance.
         """
-        self._options[index]._disabled = disabled
+        self._options[index].disabled = disabled
         if index == self.highlighted:
             self.highlighted = _widget_navigation.find_next_enabled(
                 self._options, anchor=index, direction=1
@@ -480,6 +498,8 @@ class OptionList(ScrollView, can_focus=True):
         """
 
         index = self._option_to_index[option]
+        self._mouse_hovering_over = None
+        self._pre_remove_option(option, index)
         for option in self.options[index + 1 :]:
             current_index = self._option_to_index[option]
             self._option_to_index[option] = current_index - 1
@@ -489,9 +509,19 @@ class OptionList(ScrollView, can_focus=True):
         if option._id is not None:
             del self._id_to_option[option._id]
         del self._option_to_index[option]
+        self.highlighted = self.highlighted
         self.refresh()
         return self
 
+    def _pre_remove_option(self, option: Option, index: int) -> None:
+        """Hook called prior to removing an option.
+
+        Args:
+            option: Option being removed.
+            index: Index of option being removed.
+
+        """
+
     def remove_option(self, option_id: str) -> Self:
         """Remove the option with the given ID.
 
@@ -519,9 +549,59 @@ class OptionList(ScrollView, can_focus=True):
         Raises:
             OptionDoesNotExist: If there is no option with the given index.
         """
+        try:
             option = self._options[index]
+        except IndexError:
+            raise OptionDoesNotExist(
+                f"Unable to remove; there is no option at index {index}"
+            ) from None
         return self._remove_option(option)
 
+    def _replace_option_prompt(self, index: int, prompt: VisualType) -> None:
+        """Replace the prompt of an option in the list.
+
+        Args:
+            index: The index of the option to replace the prompt of.
+            prompt: The new prompt for the option.
+
+        Raises:
+            OptionDoesNotExist: If there is no option with the given index.
+        """
+        self.get_option_at_index(index)._set_prompt(prompt)
+        self._clear_caches()
+
+    def replace_option_prompt(self, option_id: str, prompt: VisualType) -> Self:
+        """Replace the prompt of the option with the given ID.
+
+        Args:
+            option_id: The ID of the option to replace the prompt of.
+            prompt: The new prompt for the option.
+
+        Returns:
+            The `OptionList` instance.
+
+        Raises:
+            OptionDoesNotExist: If no option has the given ID.
+        """
+        self._replace_option_prompt(self.get_option_index(option_id), prompt)
+        return self
+
+    def replace_option_prompt_at_index(self, index: int, prompt: VisualType) -> Self:
+        """Replace the prompt of the option at the given index.
+
+        Args:
+            index: The index of the option to replace the prompt of.
+            prompt: The new prompt for the option.
+
+        Returns:
+            The `OptionList` instance.
+
+        Raises:
+            OptionDoesNotExist: If there is no option with the given index.
+        """
+        self._replace_option_prompt(index, prompt)
+        return self
+
     @property
     def _lines(self) -> Sequence[tuple[int, int]]:
         """A sequence of pairs of ints for each line, used internally.
@@ -549,6 +629,7 @@ class OptionList(ScrollView, can_focus=True):
     def _clear_caches(self) -> None:
         self._option_render_cache.clear()
         self._line_cache.clear()
+        self.refresh()
 
     def notify_style_update(self) -> None:
         self._clear_caches()
@@ -557,6 +638,9 @@ class OptionList(ScrollView, can_focus=True):
         self._clear_caches()
         self.refresh()
 
+    def _on_mount(self) -> None:
+        self._update_lines()
+
     def on_show(self) -> None:
         self.scroll_to_highlight()
 
@@ -567,11 +651,7 @@ class OptionList(ScrollView, can_focus=True):
             event: The click event.
         """
         clicked_option: int | None = event.style.meta.get("option")
-        if (
-            clicked_option is not None
-            and clicked_option >= 0
-            and not self._options[clicked_option].disabled
-        ):
+        if clicked_option is not None and not self._options[clicked_option].disabled:
             self.highlighted = clicked_option
             self.action_select()
 
@@ -589,7 +669,7 @@ class OptionList(ScrollView, can_focus=True):
         Args:
             event: The mouse movement event.
         """
-        self.hover_option_index = event.style.meta.get("option")
+        self._mouse_hovering_over = event.style.meta.get("option")
 
     def _on_leave(self, _: events.Leave) -> None:
         """React to the mouse leaving the widget."""
@@ -633,7 +713,7 @@ class OptionList(ScrollView, can_focus=True):
             A list of strips.
         """
         padding = self.get_component_styles("option-list--option").padding
-        width = self.content_region.width - self._get_left_gutter_width()
+        width = self.scrollable_content_region.width - self._get_left_gutter_width()
         cache_key = (option, style)
         if (strips := self._option_render_cache.get(cache_key)) is None:
             visual = self._get_visual(option)
@@ -657,14 +737,16 @@ class OptionList(ScrollView, can_focus=True):
     def _update_lines(self) -> None:
         line_cache = self._line_cache
         lines = line_cache.lines
-        last_index = lines[-1][0] if lines else 0
+        if not self.options:
+            return
+
+        next_index = lines[-1][0] + 1 if lines else 0
         get_visual = self._get_visual
         width = self.scrollable_content_region.width
 
-        if last_index < len(self.options) - 1:
+        if next_index < len(self.options):
             styles = self.get_component_styles("option-list--option")
-
-            for index, option in enumerate(self.options[last_index:], last_index):
+            for index, option in enumerate(self.options[next_index:], next_index):
                 line_cache.index_to_line[index] = len(line_cache.lines)
                 line_count = (
                     get_visual(option).get_height(styles, width) + option._divider
@@ -716,6 +798,10 @@ class OptionList(ScrollView, can_focus=True):
         strips = self._get_option_render(option, style)
         return strips[line_offset]
 
+    def render_lines(self, crop: Region) -> list[Strip]:
+        self._update_lines()
+        return super().render_lines(crop)
+
     def render_line(self, y: int) -> Strip:
         line_number = self.scroll_offset.y + y
         try:
@@ -723,25 +809,20 @@ class OptionList(ScrollView, can_focus=True):
         except IndexError:
             return Strip.blank(self.scrollable_content_region.width)
         option = self.options[option_index]
-        mouse_over = self.hover_option_index == option_index
-        component_classes: tuple[str, ...] = ("option-list--option",)
+        mouse_over = self._mouse_hovering_over == option_index
+        component_class = ""
         if option.disabled:
-            component_classes = (
-                "option-list--option",
-                "option-list--option-disabled",
-            )
+            component_class = "option-list--option-disabled"
         elif self.highlighted == option_index:
-            component_classes = (
-                "option-list--option",
-                "option-list--option-highlighted",
-            )
+            component_class = "option-list--option-highlighted"
         elif mouse_over:
-            component_classes = (
-                "option-list--option",
-                "option-list--option-hover",
-            )
+            component_class = "option-list--option-hover"
+
+        if component_class:
+            style = self.get_visual_style("option-list--option", component_class)
+        else:
+            style = self.get_visual_style("option-list--option")
 
-        style = self.get_visual_style(*component_classes)
         strips = self._get_option_render(option, style)
         strip = strips[line_offset]
         return strip
@@ -760,23 +841,28 @@ class OptionList(ScrollView, can_focus=True):
         """React to the highlighted option having changed."""
         if highlighted is None:
             return
-
         if not self._options[highlighted].disabled:
             self.scroll_to_highlight()
-
-        option: Option
-        if highlighted is None:
-            option = None
-        else:
-            option = self.options[highlighted]
-        self.post_message(self.OptionHighlighted(self, option, highlighted))
+            self.post_message(
+                self.OptionHighlighted(self, self.options[highlighted], highlighted)
+            )
 
     def scroll_to_highlight(self, top: bool = False) -> None:
+        """Scroll to the highlighted option.
+
+        Args:
+            top: Ensure highlighted option is at the top of the widget.
+        """
         highlighted = self.highlighted
         if highlighted is None or not self.is_mounted:
             return
 
+        self._update_lines()
+
+        try:
             y = self._index_to_line[highlighted]
+        except KeyError:
+            return
         option = self.options[highlighted]
         height = self._heights[highlighted] - option._divider
 
@@ -820,32 +906,35 @@ class OptionList(ScrollView, can_focus=True):
         Args:
             direction: `-1` to move up a page, `1` to move down a page.
         """
+        if not self._options:
+            return
 
-        height = self.content_region.height
-
-        option_index = self.highlighted or 0
-
-        y = min(
-            self._index_to_line[option_index] + direction * height,
+        height = self.scrollable_content_region.height
+        y = clamp(
+            self._index_to_line[self.highlighted or 0] + direction * height,
+            0,
             len(self._lines) - 1,
         )
         option_index = self._lines[y][0]
-
-        target_option = _widget_navigation.find_next_enabled_no_wrap(
+        self.highlighted = _widget_navigation.find_next_enabled_no_wrap(
             candidates=self._options,
             anchor=option_index,
             direction=direction,
             with_anchor=True,
         )
-        if target_option is not None:
-            self.highlighted = target_option
 
     def action_page_up(self):
         """Move the highlight up one page."""
+        if self.highlighted is None:
+            self.action_first()
+        else:
             self._move_page(-1)
 
     def action_page_down(self):
         """Move the highlight down one page."""
+        if self.highlighted is None:
+            self.action_last()
+        else:
             self._move_page(1)
 
     def action_select(self) -> None:
@@ -854,34 +943,9 @@ class OptionList(ScrollView, can_focus=True):
         If an option is selected then a
         [OptionList.OptionSelected][textual.widgets.OptionList.OptionSelected] will be posted.
         """
-        if self.highlighted is None:
-            return
         highlighted = self.highlighted
+        if highlighted is None:
+            return
         option = self._options[highlighted]
         if highlighted is not None and not option.disabled:
             self.post_message(self.OptionSelected(self, option, highlighted))
-
-
-if __name__ == "__main__":
-    from textual.app import App, ComposeResult
-
-    TEXT = """I must not fear.
-Fear is the [u]mind-killer[/u].
-Fear is the little-death that brings total obliteration.
-I will face my fear.
-I will permit it to pass over me and through me.
-And when it has gone past, I will turn the inner eye to see its path.
-Where the fear has gone there will be nothing. Only I will remain."""
-
-    class OLApp(App):
-
-        def compose(self) -> ComposeResult:
-            yield OptionList(
-                *(
-                    ["Hello", "World!", None, TEXT, None, "Foo", "Bar", "Baz", None]
-                    * 100
-                )
-            )
-
-    app = OLApp()
-    app.run()

src/textual/widgets/_selection_list.py

@@ -15,7 +15,12 @@ from textual import events
 from textual.binding import Binding
 from textual.messages import Message
 from textual.strip import Strip
-from textual.widgets._option_list import Option, OptionList, OptionListContent
+from textual.widgets._option_list import (
+    Option,
+    OptionDoesNotExist,
+    OptionList,
+    OptionListContent,
+)
 from textual.widgets._toggle_button import ToggleButton
 
 SelectionType = TypeVar("SelectionType")
@@ -229,6 +234,10 @@ class SelectionList(Generic[SelectionType], OptionList):
         self._send_messages = False
         """Keep track of when we're ready to start sending messages."""
         options = [self._make_selection(selection) for selection in selections]
+        self._values: dict[SelectionType, int] = {
+            option.value: index for index, option in enumerate(options)
+        }
+        """Keeps track of which value relates to which option."""
         super().__init__(
             *options,
             name=name,
@@ -237,10 +246,6 @@ class SelectionList(Generic[SelectionType], OptionList):
             disabled=disabled,
             wrap=False,
         )
-        self._values: dict[SelectionType, int] = {
-            option.value: index for index, option in enumerate(options)
-        }
-        """Keeps track of which value relates to which option."""
 
     @property
     def selected(self) -> list[SelectionType]:
@@ -510,20 +515,25 @@ class SelectionList(Generic[SelectionType], OptionList):
             A [`Strip`][textual.strip.Strip] that is the line to render.
         """
 
-        # First off, get the underlying prompt from OptionList.
-        prompt = super().render_line(y)
+        # TODO: This is rather crufty and hard to fathom. Candidate for a rewrite.
 
-        # If it looks like the prompt itself is actually an empty line...
-        if not prompt:
-            # ...get out with that. We don't need to do any more here.
-            return prompt
+        # First off, get the underlying prompt from OptionList.
+        line = super().render_line(y)
+
+        # # If it looks like the prompt itself is actually an empty line...
+        # if not prompt:
+        #     # ...get out with that. We don't need to do any more here.
+        #     return prompt
 
         # We know the prompt we're going to display, what we're going to do
         # is place a CheckBox-a-like button next to it. So to start with
         # let's pull out the actual Selection we're looking at right now.
         _, scroll_y = self.scroll_offset
         selection_index = scroll_y + y
+        try:
             selection = self.get_option_at_index(selection_index)
+        except OptionDoesNotExist:
+            return line
 
         # Figure out which component style is relevant for a checkbox on
         # this particular line.
@@ -533,10 +543,12 @@ class SelectionList(Generic[SelectionType], OptionList):
         if self.highlighted == selection_index:
             component_style += "-highlighted"
 
-        # Get the underlying style used for the prompt.
-        underlying_style = next(iter(prompt)).style
+        # # # Get the underlying style used for the prompt.
+        underlying_style = next(iter(line)).style or self.rich_style
         assert underlying_style is not None
 
+        # underlying_style = self.rich_style
+
         # Get the style for the button.
         button_style = self.get_component_rich_style(component_style)
 
@@ -565,7 +577,7 @@ class SelectionList(Generic[SelectionType], OptionList):
                 Segment(ToggleButton.BUTTON_INNER, style=button_style),
                 Segment(ToggleButton.BUTTON_RIGHT, style=side_style),
                 Segment(" ", style=underlying_style),
-                *prompt,
+                *line,
             ]
         )
 
@@ -617,24 +629,17 @@ class SelectionList(Generic[SelectionType], OptionList):
         """
         return cast("Selection[SelectionType]", super().get_option(option_id))
 
-    def _remove_option(self, index: int) -> None:
-        """Remove a selection option from the selection option list.
-
-        Args:
-            index: The index of the selection option to remove.
-
-        Raises:
-            IndexError: If there is no selection option of the given index.
-        """
-        option = self.get_option_at_index(index)
+    def _pre_remove_option(self, option: Option, index: int) -> None:
+        """Hook called prior to removing an option."""
+        assert isinstance(option, Selection)
         self._deselect(option.value)
         del self._values[option.value]
+
         # Decrement index of options after the one we just removed.
         self._values = {
             option_value: option_index - 1 if option_index > index else option_index
             for option_value, option_index in self._values.items()
         }
-        return super()._remove_option(index)
 
     def add_options(
         self,

tests/option_list/test_option_list_create.py

@@ -6,12 +6,7 @@ import pytest
 
 from textual.app import App, ComposeResult
 from textual.widgets import OptionList
-from textual.widgets.option_list import (
-    DuplicateID,
-    Option,
-    OptionDoesNotExist,
-    Separator,
-)
+from textual.widgets.option_list import DuplicateID, Option, OptionDoesNotExist
 
 
 class OptionListApp(App[None]):
@@ -21,7 +16,7 @@ class OptionListApp(App[None]):
         yield OptionList(
             "0",
             Option("1"),
-            Separator(),
+            None,
             Option("2", disabled=True),
             None,
             Option("3", id="3"),

tests/option_list/test_option_list_mouse_click.py

@@ -3,7 +3,7 @@ from __future__ import annotations
 from textual import on
 from textual.app import App, ComposeResult
 from textual.widgets import OptionList
-from textual.widgets.option_list import Option, Separator
+from textual.widgets.option_list import Option
 
 
 class OptionListApp(App[None]):
@@ -12,7 +12,7 @@ class OptionListApp(App[None]):
     def compose(self) -> ComposeResult:
         yield OptionList(
             Option("0"),
-            Separator(),
+            None,
             Option("1"),
         )