<!--
  if you use RichText like this it doesn't render the columns

-->

<s:RichText
			textFlow="{TextFlowUtil.importFromXML(textFlowXML)}"
                        columnCount="3"
			
			left="50" right="50" top="100" bottom="100"
			/>

<!-- 
  but if you wrap it in a group and use the groups dimensions it works ...
-->

<s:Group
		id="textBlock"
		left="50" right="50" top="100" bottom="100"
		>
		<s:RichText
			textFlow="{TextFlowUtil.importFromXML(textFlowXML)}"
                        columnCount="3"
			
			width="{textBlock.width}"
			height="{textBlock.height}"
			/>
	</s:Group>

<!--
  if you use RichText like this it doesn't render the columns

-->

<s:RichText
			textFlow="{TextFlowUtil.importFromXML(textFlowXML)}"
                        columnCount="3"
			
			left="50" right="50" top="100" bottom="100"
			/>

<!-- 
  but if you wrap it in a group and use the groups dimensions it works ...
-->

<s:Group
		id="textBlock"
		left="50" right="50" top="100" bottom="100"
		>
		<s:RichText
			textFlow="{TextFlowUtil.importFromXML(textFlowXML)}"
			
			width="{textBlock.width}"
			height="{textBlock.height}"
			/>
	</s:Group>

<!--
  if you use RichText like this it doesn't render the columns

-->

<s:RichText
			
			includeIn="case_studies"
			textFlow="{TextFlowUtil.importFromXML(textFlowXML)}"
                        columnCount="3"
			
			left="50" right="50"
		        top="100" bottom="100"
			/>

<!-- 
  but if you wrap it in a group and use the groups dimensions it works ...
-->

<s:Group
		id="textBlock"
		left="50" right="50"
		top="100" bottom="100"
		>
		<s:RichText
			
			includeIn="case_studies"
			textFlow="{TextFlowUtil.importFromXML(textFlowXML)}"
			
			width="{textBlock.width}"
			height="{textBlock.height}"
			/>
	</s:Group>

Seems to be a bug with RichText if you are using columnCount and using dynamic sizing of your component.

Spark RichText and columns bug

MXML