If you end up with a heat map with too many data points on it, it can be difficult to analyze. If the points are tightly clustered, you can use the Zooming function to focus attention on a subset of the risks.
Select the data points you want to zoom in on by drawing a rectangle around the points with your mouse (similar to selecting multiple files in folder on your PC). The data points you selected will be highlighted with a white border. In this example numbers 6,7,18,4,23,8,10.
Right-click the chart background and choose Zoom in on selected items. The result is a heat map that focuses on the values you selected with an automatically narrowed legend, thereby spreading them out for easier viewing.
To zoom out again, right-click the chart background and deselect Zoom in on selected items.