Fix #8753.

- Store whether or not the use of the horizontal scrollbar is desired
  on the class itself. If the CLV was set to use the horizontal scrollbar,
  and then asked to lay itself out while hidden, it would incorrectly assume
  the horizontal scrollbar wasn't in use, and consequently repositioned its
  views such that the horizontal scrollbar and outline view overlapped.

headers/private/interface/ColumnListView.h

@@ -385,9 +385,8 @@ protected:
 	virtual	void				DoLayout();
 
 private:
-			void				_Init(bool showHorizontalScrollbar);
+			void				_Init();
 			void				_GetChildViewRects(const BRect& bounds,
-									bool showHorizontalScrollBar,
 									BRect& titleRect, BRect& outlineRect,
 									BRect& vScrollBarRect,
 									BRect& hScrollBarRect);
@@ -404,6 +403,7 @@ private:
 			bool				fSortingEnabled;
 			float				fLatchWidth;
 			border_style		fBorderStyle;
+			bool				fShowingHorizontalScrollBar;
 };
 
 #endif // _COLUMN_LIST_VIEW_H