Feature request: Edit Extended Field dropdown field list

My drop down list of tags to choose from has gotten out of hand. I would use a certain tag field name for awhile then change it later after I got a better understanding of what was more 'standard'. But then I forget which one is the most proper to use out of all the different options. I would like to have some way of removing these fields, either through a text file or the options menu. I tried removing field entries from the configuration file manually but it got corrupted.

Do I understand you correctly, that you have created numerous user defined fields in mp3 files and now you would like to rename them?
If this is so, then be aware that mp3tag only displays "what is there". So if you want to get rid of a field you actually have to delete it in every file, that is physically remove it.
Also renaming cannot be done just by modifying a label but this alteration has to be written into every file.
Or what is your problem (I honestly had some difficulties to understand what you deleted from the configuration file...)
Could you tell which dialog or which screen section you are talking about? Thx

I'm talking about the dropdown list of field names that is given for the Add field... button in the Extended Tags window or any action that involves formatting a tag. This list isn't based off of the tags in song files; it is based on a list in the configuration file. A new field is added every time you use a different value for the field. So if I were to accidentally add a tag with the field "OOPS", then that would be permanently available in the dropdown list. Even if I were to remove the offending tag. If I open the configuration file and do a text search, I can find OOPS but if I try deleting it, the configuration gets corrupted because it is mixed in with binary code.

You can delete those by pressing [Shift+Del] and confirming the change with OK.

Thank you! I spent awhile looking through the help documentation and couldn't find it. If it's not there it might be a good idea to add it for others who would have same problem.

Well, I have pressed [Shift+Del] about 100 times to clear the complete history list, meanwhile I got a cramp in my fingers, but then ... after some minutes ... how can the dialog be closed to make the changes really happen?
Pressing OK does not work at this point.

DD.20100409.0920.CEST

After deleting fields, make sure you actually add a tag to the file rather than press cancel. A wonky way of confirming the changes but it works.