On Viewpoint Query Monitor's Top Sessions Graph of the Summary view, two metrics are represented: one by the length of the bar and the other by the color or shading of the bar. The user chooses a metric left of the graph. How is that metric displayed (length of bar or color/shading)? What is the other metric? Is there a way to set the thresholds on the metrics similar to the Display button on Capacity Heatmap?
The Top Sessions graph only plots out information on one metric, not two. The bar graph is used to display sessions with the largest values of the selected metric to be blocks with a relative size of the metric value. The color / shading is just used to highlight for differentation of the different blocks going from darket (highest metric value) to lightest (lesser metric value).
Regarding thresholds, you cannot set these within the sessions graph bar but can in the table display below through table actions - configure columns - set thresholds. This will color highlight the outlier metrics exceeding the set threshold.