fix(ui): isolate scroll-button state from pop-outs and tidy toolbar

Guard _childScrolledUp writes behind updateScrollState param so pop-out
windows no longer contaminate the main window's scroll state. Widen the
honorific title slot budget when the scroll button is visible, fix stale
comment, and apply csharpier formatting.

HellionChat/Ui/ChatLogWindow.cs

@@ -781,7 +781,7 @@ public sealed class ChatLogWindow : Window
     private bool _scrollToBottomRequested;
 
     // UI-5: cached each frame inside the ##chat2-messages child. True when the
-    // user has scrolled up enough that the overlay button should be shown.
+    // user has scrolled up enough that the toolbar button should be shown.
     private bool _childScrolledUp;
 
     public override void Draw()
@@ -1544,7 +1544,13 @@ public sealed class ChatLogWindow : Window
         CurrentHideState = HideState.User;
     }
 
-    internal void DrawMessageLog(Tab tab, PayloadHandler handler, float childHeight, bool switchedTab)
+    internal void DrawMessageLog(
+        Tab tab,
+        PayloadHandler handler,
+        float childHeight,
+        bool switchedTab,
+        bool updateScrollState = true
+    )
     {
         using (var child = ImRaii.Child("##chat2-messages", new Vector2(-1, childHeight)))
         {
@@ -1557,11 +1563,14 @@ public sealed class ChatLogWindow : Window
 
                 // Cached for the header toolbar's scroll-to-bottom button, which is
                 // drawn one frame later. GetScrollMaxY / GetScrollY here refer to
-                // the child's scroll context.
+                // the child's scroll context. Pop-out windows pass updateScrollState:
+                // false so they do not overwrite the main window's cached state.
+                if (updateScrollState)
                     _childScrolledUp = ImGui.GetScrollMaxY() - ImGui.GetScrollY() > 1f;
             }
             else
             {
+                if (updateScrollState)
                     _childScrolledUp = false;
             }
         }
@@ -1603,15 +1612,17 @@ public sealed class ChatLogWindow : Window
                 // Custom styles can have cellPadding that go above 4, which GetScrollY isn't respecting
                 var cellPaddingOffset =
                     !compact && oldCellPadding.Y > 4f ? oldCellPadding.Y - 4f : 0f;
-                if (switchedTab || _scrollToBottomRequested
-                    || ImGui.GetScrollY() + cellPaddingOffset >= ImGui.GetScrollMaxY())
+                if (
+                    switchedTab
+                    || _scrollToBottomRequested
+                    || ImGui.GetScrollY() + cellPaddingOffset >= ImGui.GetScrollMaxY()
+                )
                     ImGui.SetScrollHereY(1f);
                 _scrollToBottomRequested = false;
 
                 handler.Draw();
             }
         }
-
     }
 
     private void DrawMessages(
@@ -2349,7 +2360,12 @@ public sealed class ChatLogWindow : Window
         var spacing = ImGui.GetStyle().ItemSpacing.X;
         ImGui.SetCursorPosX(ImGui.GetCursorPosX() + avail - 2 * iconWidth - spacing);
 
-        if (ImGuiUtil.IconButton(FontAwesomeIcon.ArrowDown, tooltip: HellionStrings.ChatLog_ScrollToBottom_Tooltip))
+        if (
+            ImGuiUtil.IconButton(
+                FontAwesomeIcon.ArrowDown,
+                tooltip: HellionStrings.ChatLog_ScrollToBottom_Tooltip
+            )
+        )
             _scrollToBottomRequested = true;
 
         // Keep the pop-out button on the same toolbar row. Without this the
@@ -2408,7 +2424,13 @@ public sealed class ChatLogWindow : Window
             crownWidth = ImGui.CalcTextSize(FontAwesomeIcon.Crown.ToIconString()).X;
         }
 
-        var maxTitleWidth = avail - iconWidth - gapBeforeButton - crownWidth - gapAfterCrown;
+        // When the scroll button is also present it occupies iconWidth + ItemSpacing.X
+        // to the left of the pop-out button, so shrink the title budget accordingly.
+        var scrollButtonReserve = _childScrolledUp
+            ? iconWidth + ImGui.GetStyle().ItemSpacing.X
+            : 0f;
+        var maxTitleWidth =
+            avail - iconWidth - scrollButtonReserve - gapBeforeButton - crownWidth - gapAfterCrown;
         if (maxTitleWidth <= 0)
         {
             return;

HellionChat/Ui/Popout.cs

@@ -118,7 +118,7 @@ internal class Popout : Window
 
         var handler = ChatLogWindow.HandlerLender.Borrow();
         var logHeight = ImGui.GetContentRegionAvail().Y - inputBarHeight - hintBannerHeight;
-        ChatLogWindow.DrawMessageLog(Tab, handler, logHeight, false);
+        ChatLogWindow.DrawMessageLog(Tab, handler, logHeight, false, updateScrollState: false);
 
         if (inputEnabled && InputBar != null)
         {