When you move the mouse cursor over the variable ConnectedRegions you see that it contains 98 regions.
Right-click the icon ConnectedRegions and select Clear / Display to display only the connected regions in the graphics window. Right-click again and select Display Content ▹ Select.... This menu entry opens a variable inspection window which lists the contents of the variable ConnectedRegions. The selected region of this inspection window is displayed in the graphics window using the current visualization settings. Set Draw to `margin' and Shape to `ellipse' and select some regions from the list. An example is illustrated in figure 4.6.
For now, close the variable inspection window. The large number of regions is due to the coarse setting of the bounds of the threshold operator. In the following we will use one of HDevelop's visual tools to find more appropriate settings interactively.