replace hack in scrollbars

src/textual/_styles_cache.py

@@ -49,7 +49,7 @@ def style_links(
         _Segment(
             text,
             (style + link_style if style is not None else None)
-            if (style and style._link_id == link_id)
+            if (style and not style._null and style._link_id == link_id)
             else style,
             control,
         )

src/textual/scrollbar.py

@@ -207,6 +207,7 @@ class ScrollBar(Widget):
         self.thickness = thickness
         self.grabbed_position: float = 0
         super().__init__(name=name)
+        self.auto_links = False
 
     window_virtual_size: Reactive[int] = Reactive(100)
     window_size: Reactive[int] = Reactive(0)
@@ -222,17 +223,6 @@ class ScrollBar(Widget):
         if self.thickness > 1:
             yield "thickness", self.thickness
 
-    @property
-    def link_style(self) -> Style:
-        return NULL_STYLE
-
-    @property
-    def link_hover_style(self) -> Style:
-        return NULL_STYLE
-
-    def watch_hover_style(self, old_style: Style, new_style: Style) -> None:
-        pass
-
     def render(self) -> RenderableType:
         styles = self.parent.styles
         background = (