fix for update region

src/textual/_compositor.py

@@ -384,6 +384,9 @@ class Compositor:
                     spatial_map, arranged_widgets, spacing = widget._arrange(
                         child_region.size
                     )
+                    total_region = total_region.union(
+                        spatial_map.total_region.grow(spacing)
+                    )
 
                     placements = spatial_map.get_placements(
                         child_region.reset_offset.translate(widget.scroll_offset)
@@ -402,16 +405,11 @@ class Compositor:
                     get_layer_index = layers_to_index.get
 
                     # Add all the widgets
-                    for sub_region, margin, sub_widget, z, fixed in reversed(
-                        placements
-                    ):
+                    for sub_region, _, sub_widget, z, fixed in reversed(placements):
                         # Combine regions with children to calculate the "virtual size"
                         if fixed:
                             widget_region = sub_region + placement_offset
                         else:
-                            total_region = total_region.union(
-                                sub_region.grow(spacing + margin)
-                            )
                             widget_region = sub_region + placement_scroll_offset
 
                         widget_order = order + (

src/textual/_spatial_map.py

@@ -3,10 +3,10 @@ from __future__ import annotations
 from collections import defaultdict
 from itertools import product
 from operator import attrgetter
-from typing import Iterable, Mapping, Sequence
+from typing import Iterable, Sequence
 
 from ._layout import WidgetPlacement
-from .geometry import Region
+from .geometry import Region, Spacing
 from ._partition import partition
 
 
@@ -26,10 +26,12 @@ class SpatialMap:
     def __init__(
         self,
         placements: Sequence[WidgetPlacement],
+        *,
         block_width: int = 80,
         block_height: int = 80,
     ) -> None:
         self._placements = placements
+        self._total_region = Region()
         self._block_width = block_width
         self._block_height = block_height
         self._fixed: list[WidgetPlacement] = []
@@ -37,6 +39,8 @@ class SpatialMap:
 
         self.placement_map = self._build_placements(placements)
 
+        print("SPATIAL", len(placements))
+
     def __iter__(self) -> Iterable[WidgetPlacement]:
         yield from self._placements
 
@@ -57,6 +61,14 @@ class SpatialMap:
         block_width = self._block_width
         block_height = self._block_height
 
+        self.total_region = Region.from_union(
+            [
+                placement.region.grow(placement.margin)
+                for placement in placements
+                if not placement.fixed
+            ]
+        )
+
         placements, self._fixed = partition(attrgetter("fixed"), placements)
 
         for placement in placements:

src/textual/_styles_cache.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from functools import lru_cache
+from sys import intern
 from typing import TYPE_CHECKING, Callable, Iterable, List
 
 from rich.segment import Segment
@@ -52,6 +54,20 @@ def style_links(
     return segments
 
 
+@lru_cache(1024 * 8)
+def make_blank(width, style: Style) -> Segment:
+    """Make a blank segment.
+
+    Args:
+        width (_type_): Width of blank.
+        style (Style): Style of blank.
+
+    Returns:
+        Segment: A single segment
+    """
+    return Segment(intern(" " * width), style)
+
+
 class StylesCache:
     """Responsible for rendering CSS Styles and keeping a cache of rendered lines.
 
@@ -319,20 +335,20 @@ class StylesCache:
             right_style = from_color(color=(background + border_right_color).rich_color)
             right = get_box(border_right, inner, outer, right_style)[1][2]
             if border_left and border_right:
-                line = [left, Segment(" " * (width - 2), background_style), right]
+                line = [left, make_blank(width - 2, background_style), right]
             elif border_left:
-                line = [left, Segment(" " * (width - 1), background_style)]
+                line = [left, make_blank(width - 1, background_style)]
             elif border_right:
-                line = [Segment(" " * (width - 1), background_style), right]
+                line = [make_blank(width, background_style), right]
             else:
-                line = [Segment(" " * width, background_style)]
+                line = [make_blank(width, background_style)]
         else:
             # Content with border and padding (C)
             content_y = y - gutter.top
             if content_y < content_height:
                 line = render_content_line(y - gutter.top)
             else:
-                line = [Segment(" " * content_width, inner)]
+                line = [make_blank(content_width, inner)]
             if inner:
                 line = Segment.apply_style(line, inner)
             line = line_pad(line, pad_left, pad_right, inner)

src/textual/css/_style_properties.py

@@ -305,7 +305,7 @@ class BoxProperty:
             current_value: tuple[str, Color] = cast(
                 "tuple[str, Color]", obj.get_rule(self.name)
             )
-            has_edge = current_value and current_value[0]
+            has_edge = bool(current_value and current_value[0])
             new_edge = bool(_type)
             if obj.set_rule(self.name, new_value):
                 obj.refresh(layout=has_edge != new_edge)

src/textual/css/styles.py

@@ -594,8 +594,10 @@ class Styles(StylesBase):
         Returns:
             bool: ``True`` if a rule was cleared, or ``False`` if it was already not set.
         """
-        self._updates += 1
-        return self._rules.pop(rule, None) is not None
+        changed = self._rules.pop(rule, None) is not None
+        if changed:
+            self._updates += 1
+        return changed
 
     def get_rules(self) -> RulesMap:
         return self._rules.copy()
@@ -610,12 +612,17 @@ class Styles(StylesBase):
         Returns:
             bool: ``True`` if the rule changed, otherwise ``False``.
         """
-        self._updates += 1
         if value is None:
-            return self._rules.pop(rule, None) is not None
+            changed = self._rules.pop(rule, None) is not None
+            if changed:
+                self._updates += 1
+            return changed
         current = self._rules.get(rule)
         self._rules[rule] = value
-        return current != value
+        changed = current != value
+        if changed:
+            self._updates += 1
+        return changed
 
     def get_rule(self, rule: str, default: object = None) -> object:
         return self._rules.get(rule, default)