diff --git a/src/textual_dev/previews/borders.py b/src/textual_dev/previews/borders.py
index 880b532..f4d86a4 100644
--- a/src/textual_dev/previews/borders.py
+++ b/src/textual_dev/previews/borders.py
@@ -68,7 +68,8 @@ def on_option_list_option_highlighted(
     def update_border(self, _) -> None:
         self.text.styles.border = (
             cast(
-                EdgeType, self.sidebar.get_option_at_index(self.sidebar.highlighted).id
+                EdgeType,
+                self.sidebar.get_option_at_index(self.sidebar.highlighted or 0).id,
             ),
             self.theme_variables["border"],
         )
diff --git a/src/textual_dev/previews/easing.py b/src/textual_dev/previews/easing.py
index 10ad919..e0e83b6 100644
--- a/src/textual_dev/previews/easing.py
+++ b/src/textual_dev/previews/easing.py
@@ -62,7 +62,6 @@ def on_load(self) -> None:
         self.bind(
             "ctrl+p", "focus('duration-input')", description="Focus: Duration Input"
         )
-        self.bind("ctrl+b", "toggle_dark", description="Toggle Dark")
 
     def compose(self) -> ComposeResult:
         self.animated_bar = Bar()
@@ -112,9 +111,6 @@ def on_input_changed(self, event: Input.Changed) -> None:
             if new_duration is not None:
                 self.duration = new_duration
 
-    def action_toggle_dark(self) -> None:
-        self.dark = not self.dark
-
 
 def _try_float(string: str) -> float | None:
     try: