Should trees always be in a sorted order? I am designing a tree navigation for a desktop application and wanted to know whether it should always be in sorted order (alphabetically). Windows guidelines tell is should. Or is it easier that when user creates a new folder/file it creates wherever user wants it rather than the file changing its position when the tree is by default sorted.
The implementation of trees in either navigation or organisation purposes (or both) only works if there is some order (and hierarchy) through which the user can traverse to find what they are looking for. So there has to be some sort order by default anyway.
If you are asking whether it should always be sorted in a particular way by default (e.g. alphabetically), the answer is that it depends. I think you'll find that if you are using trees to organise content then alphabetical is a safe default if the keywords and categories are clear to the user. Otherwise you'll find that there are other sort orders like creation date, modified date, user-defined order (so movable), last modified, amount of content, etc. that might make more sense in different contexts.
There are also hybrid strategies (your Windows example is one) where there are set default folders (e.g. Inbox, Trash, Spam) then the user can create their own folders and sort them in whichever order they like. I think when you look into the level of nesting then you'll find that alphabetical sorting is less important because you can't see everything at once and it might make less sense to sort it alphabetically as the groupings or categorisation becomes more important.