Often, you want to break down a feature into a set of subfeatures, or, more generally, break down a task into smaller subtasks. FogBugz subcases allow you to do so quickly and easily.
While viewing a set of cases in the grid view, you can add a subcase to any case by selecting it and clicking the "Add Subcase" button at the bottom of the screen. (Alternatively, you can select the "Add Subcase" option in the context menu.)
Once the case is created, it appears indented below the parent case, in an "outline" format. You can make the outline as deep and detailed as you like by creating subcases of subcases, and so on. Cases matching the current filter are displayed in blue, while parents of cases matching the filter (but do not themselves match) are displayed in gray.
If you prefer not to see "outlines" in your case list, you can switch from "Outline View" to "Flat View" using the control on the upper right of the case list.
You can also add subcases to a case in the case view by using the subcases field. You can find an existing case by title via auto-complete, or create a new case on the fly by entering a new title.
In the case view, you can also make the current case the subcase of another case by using the "parent" field.
It's usually best practice to create case outlines such that only cases without subcases (ie, the "bare tasks") require estimates. (You can, however, enter an estimate for a parent case.) The the grid view, the estimate of a parent case is displayed as a sum of its own estimate and all subcase estimates.
When you resolve or close a case that contains subcases, FogBugz gives you the option to perform the same action on all subcases. To do so, simply click the checkbox below the "Resolve" or "Close" buttons.
