I have this very annoying problem with an ArcMap extension in the attribute table, every column of type String cannot be sorted at all. Initially, I thought the problem was only affecting DateTimes converted to Strings, so I changed one of these fields to "esriFieldTypeDate" and it worked.
Unfortunately, none of the columns using Strings can be sorted. If the initial order by IDs is changed from another sort, and then I try to sort a String column, it gets back to this initial order. The application I am working on really needs to allow sorting strings in the Attribute table, for example with hundreds of lines it is required to be able to sort by names.
I guess the default Attribute table should be capable of comparing strings without implemeting my own Compare method.
Since I found absolutely nothing about this particular problem, I was asking myself if may be a simple formatting or encoding problem on the Strings ?
