     [Inspectable(category="General", enumeration="left,right,center,justify,contentJustify", defaultValue="left")]
 
     /** 
-     *  The horizontal alignment of container children.
+     *  The horizontal alignment of layout elements.
      *  If the value is <code>"left"</code>, <code>"right"</code>, or <code>"center"</code> then the 
-     *  child is aligned relative to the container's <code>contentWidth</code> property.
-     * 
-     *  <p>If the value is <code>"contentJustify"</code>, then the child's actual
+     *  layout element is aligned relative to the container's <code>contentWidth</code> property.
+     * 
+     *  <p>If the value is <code>"contentJustify"</code>, then the layout element's actual
      *  width is set to the <code>contentWidth</code> of the container.
-     *  The <code>contentWidth</code> of the container is the width of the largest child. 
-     *  If all children are smaller than the width of the container, 
-     *  then set the width of all the children to the width of the container.</p>
-     * 
-     *  <p>If the value is <code>"justify"</code> then the child's actual width
+     *  The <code>contentWidth</code> of the container is the width of the largest layout element. 
+     *  If all layout elements are smaller than the width of the container, 
+     *  then set the width of all layout elements to the width of the container.</p>
+     * 
+     *  <p>If the value is <code>"justify"</code> then the layout element's actual width
      *  is set to the container's width.</p>
      *
      *  <p>This property does not affect the layout's measured size.</p>

    
    /**
     *  Returns 1.0 if the specified index is completely in view, 0.0 if
     *  it's not, and a value in between if the index is partially 
     *  within the view.
     * 
     *  An index is "in view" if the corresponding non-null layout element is 
     *  within the vertical limits of the layout target's scrollRect
     *  and included in the layout.
     * 
     *  If the specified index is partially within the view, the 
     *  returned value is the percentage of the corresponding layout
     *  element that's visible.
     * 
     *  Returns 0.0 if the specified index is invalid or if it corresponds to
     *  null element, or a ILayoutElement for which includeInLayout is false.
     * 
     *  @return the percentage of the specified element that's in view.
     *  @see firstIndexInView
     *  @see lastIndexInView
     *  
     *  @langversion 3.0
     *  @playerversion Flash 10

import spark.layouts.supportClasses.LinearLayoutVector;

/**
 *  The VerticalLayout class arranges the layout elements in a vertical sequence,
 *  top to bottom, with optional gaps between the elements and optional padding
 *  around the sequence of elements.
 *
 *  <p>The vertical position of the elements is determined by arranging them
 *  in a vertical sequence, top to bottom, taking into account the padding
 *  before the first element and the gaps between the elements.</p>
 *
 *  <p>The horizontal position of the elements is determined by the layout's
 *  <code>horizontalAlign</code> property.</p>
 *
 *  <p>During the execution of the <code>measure()</code> method, 
 *  the default size of the container is calculated by
 *  accumulating the preferred sizes of the elements, including gaps and padding.
 *  When <code>requestedRowCount</code> is set, only the space for that many elements
 *  is measured, starting from the first element.</p>
 *
 *  <p>During the execution of the <code>updateDisplayList()</code> method, 
 *  the height of each element is calculated
 *  according to the following rules, listed in their respective order of
 *  precedence (element's minimum height and maximum height are always respected):</p>
 *  <ul>
 *    <li>If <code>variableRowHeight</code> is <code>false</code>, 
 *    then set the element's height to the
 *    value of the <code>rowHeight</code> property.</li>
 *
 *    <li>If the element's <code>percentHeight</code> is set, then calculate the element's
 *    height by distributing the available container height between all
 *    elements with a <code>percentHeight</code> setting. 
 *    The available container height
 *    is equal to the container height minus the gaps, the padding and the
 *    space occupied by the rest of the elements. The element's <code>precentHeight</code>
 *    property is ignored when the layout is virtualized.</li>
 *
 *    <li>Set the element's height to its preferred height.</li>
 *  </ul>
 *
 *  <p>The width of each element is calculated according to the following rules,
 *  listed in their respective order of precedence (element's minimum width and
 *  maximum width are always respected):</p>
 *  <ul>
 *    <li>If <code>horizontalAlign</code> is <code>"justify"</code>, 
 *    then set the element's width to the container width.</li>
 *
 *    <li>If <code>horizontalAlign</code> is <code>"contentJustify"</code>,
 *    then set the element's width to the maximum between the container's width 
 *    and all elements' preferred width.</li>
 *
 *    <li>If the element's <code>percentWidth</code> is set, then calculate the element's
 *    width as a percentage of the container's width.</li>
 *
 *    <li>Set the element's width to its preferred width.</li>
 *  </ul>
 *
 *  @mxml 
 *  <p>The <code>&lt;VerticalLayout&gt;</code> tag inherits all of the tag 
 *  attributes of its superclass and adds the following tag attributes:</p>
 *
 *  <pre>
 *  &lt;VerticalLayout 
 *    <strong>Properties</strong>
 *    gap="6"
 *    horizontalAlign="left"
 *    paddingBottom="0"
 *    paddingLeft="0"
 *    paddingRight="0"
 *    paddingTop="0"
 *    requestedRowCount="-1"
 *    rowHeight="<i>calculated</i>"
 *    variableRowHeight="true"
 *  /&gt;
 *  </pre>
 *
 *  @langversion 3.0
 *  @playerversion Flash 10
