A great resource...
Displaying a categorized view as
flat
If your view is a categorized view built
in Designer Release 5.0 or later, you can select "Categorized is flat
version 5 or greater" to convert your view to a non-hierarchical,
flat view, which displays all documents on a single level. Use this feature
if your level of indentation in a view exceeds the limit of 32 levels.