When sorting files in an archive, you might initially want to do a rough sorting.
To this end, you can apply tags to selected files based on whether they're Tagged (for example approved for keeping), Rejected (files you don't want to keep), or Unclassified (assets you have not yet tagged for one or the other).
How to apply tags
Using the keyboard for navigation, you can apply tags using the T (Tagged), R (Rejected), and U (Unclassified) keys. You can tag files from the Thumbnail Grid view or any other view in FotoStation, such as the selection carousel; even in preview windows.
Note: This method applies the same tags as when using the Basic Classify View - it's just another means to an end.
Filtering by tags
Having tagged a number of assets, you can apply a filter to only display files with a given tag: Use Shift-T/R/U to display files marked as Tagged, Rejected, and/or Unclassified, respectively. The keyboard shortcut can be used to toggle the filter on and off.
Tip: Before you start tagging files in an archive, select Shift-U to display all Unclassified files (in practice, at this point all files that have not yet been classified will be shown). Then, as you choose to keep or reject files using the T and R keys they will disappear from view to help you keep track of which files remain to be tagged.
This feature is also very practical for isolating photos that you have tagged directly in your camera.