I created a dimension style in a drawing, a co-worker opened a read only copy of that drawing, and did a "save as." He now has an issue that is causing us grief. The dimension style has changed in his drawing that now includes $0 in the name. It also has a completely different look to it. It doesn't show up in the dimension style editor. the only way I can detect it is in the properties box.
If you want to create a child dimension style from the command line to be used for linear dimensions, you set your dim variables then save it as the parent dimension style name with $0 on the end.
It is not supposed to show up in the dimstyle manager that way, but I have seen it happen before. If purging does not get rid of it then change your existing dimensions to a different style and then purge.
Just insert a drawing with a good dimension in it to get the style back.