The data source selection appears on several windows: lists, bulk operations, user defined building blocks, and hyperlinked cells.

In the upper image above, no data source is defined. You have the options of creating one or selecting an existing one. If you create one, it will be nested inside the building block you are working on.

In the lower image, a nested data source is shown. You have the options of opening it, changing it (see below), or choosing a table. In cases where the data set has more than one table, only one of the tables can act as the basis for a list or or other building block.

The changes that you can make to a nested building block are:

• You can save it with a name. This converts the data source from a nested building block to a named reference.

• You can delete it.

If you want to start over, you have to delete or unlink the data source to return the display to "Nothing" (the top image above) before you can choose a different data source.