     {
         const r:Rectangle = visibleItemRenderersBounds;
         const width:Number = r.width;  
-        const height:Number = 1; // TBD: should be max(1, colGap)
+        const height:Number = separator.getPreferredBoundsHeight();
         const x:Number = r.x;
         const rowCount:int = gridDimensions.rowCount;
         const bounds:Rectangle = (rowIndex < rowCount) 

    private function layoutHeaderSeparator(separator:IVisualElement, columnIndex:int):void
    {
        var columnHeaderBar:ColumnHeaderBar = getColumnHeaderBar();
        const width:Number = 1;  // TBD: should be max(1, rowGap)
        const height:Number = columnHeaderBar.height; 
        const columnBounds:Rectangle = gridDimensions.getColumnBounds(columnIndex);
        
        if (!columnBounds)
            return;

        const x:Number = columnBounds.right;
        const y:Number = columnBounds.top;
        layoutGridElement(separator, x, y, width, height);

        if (!bounds)
            return;
     
        const y:Number = bounds.bottom; // TBD: should center on gap here.
        layoutGridElement(separator, x, y, width, height);
    }
    
    private function layoutColumnSeparator(separator:IVisualElement, columnIndex:int):void
    {
        const r:Rectangle = visibleItemRenderersBounds;
        const width:Number = separator.getPreferredBoundsWidth();
        const height:Number = Math.max(r.height, visibleGridBounds.height); 
        const bounds:Rectangle = gridDimensions.getColumnBounds(columnIndex);
        
        if (!bounds)
            return;

        const x:Number = bounds.right; // TBD: should center on gap here.
        const y:Number = r.y;
        layoutGridElement(separator, x, y, width, height);
    }
