I added a large number of taxonomy terms in the order I want. Their term IDs reflect they are added in the correct order. However, everywhere they are displayed alphabetically. Particularly, inside a hierarchical select widget they are displayed alphabetically - when I see their IDs (856, 847, 843 - not a correct numeric order but correct alphabetic A, B, C) they check out fine so they were added properly. How can I control this?
The order in which you enter the taxonomy terms is not important to how they are displayed. Drupal defaults to alphabetic ordering, but you can adjust this order manually.
Go to Content management > Taxonomy > Your vocabulary: List terms (via
admin/content/taxonomy/list) and reorder the terms by dragging the handle on the left. This is also the order Hierarchical Select uses.
You can also try out Taxonomy Manager to see if this provides you with a better interface for reordering large numbers of terms.
What version of Drupal? There's a module for D6 called TagOrder that'll probably do what you want. If you're in D7 you may need to see if there's a port of it or an equivalent: http://drupal.org/project/tagorder