I have removed Wysiwyg Version 2! from some of my Sites and replaced it with ckeditor.
The wysiwyg folder is left there because some other installed sites could use it in an multisite environment.
And now i get some incompatibility Warnings about Wysiwyg and an advice to update it from 1.0 to 2.0, even when there is no version 1.0 on the whole server and all versions installed to the database are removed.
I couldn't find an explanation for this in the Database.