...
You can switch the Workflow Monitor display mode, which by default shows icons that represent task instance types, so that the icons represent task instance status types, as shown in the following example.
In this mode, statuses are grouped into categories, and the border colors for those categories are as follow.
| Status Type | Color |
|---|---|
| Not Running | gray #808080 |
| Problem | green #008000 |
| Complete | red #EE0000 |
| Unknown | black #000000 |
To switch display modes, click the Toggle Vertex Style icon 
.
...