Objects with the following properties:
caption [type: String] - The caption of the analysis element usage to display in the tooltip.
analysisElementCaption [type: String, optional: true] - The caption of the analysis element, which is used for keywords. (If not specified, caption will be used.)
placement [type: dundas.data.PlacementPosition] - The placement of the analysis element usage in the metric set.
index [type: Number, integer: true] - The index of the analysis element usage within its placement in the metric set.