AXWebArea AXRoleDescription='HTML content'
++AXGroup AXRoleDescription='group'
++++AXGroup AXSubrole=AXDocumentMath AXRoleDescription='math'
++++++AXStaticText AXRoleDescription='text' AXValue='a'
++++++AXStaticText AXRoleDescription='text' AXValue='2'
++++++AXStaticText AXRoleDescription='text' AXValue='+'
++++++AXStaticText AXRoleDescription='text' AXValue='b'
++++++AXStaticText AXRoleDescription='text' AXValue='2'
