is it not possible to add dummy to the list of items ?

sometimes we need to use the tag-filename convertion option. if i have something like the following as title {name of file(unwanted items)}then i may need the dummy item to remove the unwanted portion of the title. but this "dummy" is not provided. as a result every time i use this option i have to type the word dummy. is it not easy to provide that item also with other items like filename, artist. album etc? thanks.

Hm .. I am rather sure ...
... there is no tag-field defined in Mp3tag for special purpose, which is named DUMMY.
When you type 'dummy' in one of your Mp3tag scripting expressions, you will get only the text string 'dummy' (without the quotes, certainly).

It is allowed that you can create a user-defined tag-field with the name DUMMY and fill it with a value of your wish.
Then you can use the tag-field name DUMMY, respectively the tag-field value %DUMMY%, in your scripting expressions.
Once instantiated the name "DUMMY" will be available in Mp3tag picklists.

When an user-defined tag-field exist with the name DUMMY, this will make the Mp3tag system defined placeholder %DUMMY% invisible.

The Mp3tag system placeholder %DUMMY% has two tasks ...
... when read from ... it delivers nothing,
... when written to ... it sucks everything.

From my point of view, when someone use the converter "Tag - Filename", ...
... there is no ... should I say never ... the need to use the system placeholder %DUMMY%.
It makes no sense to create a filename from nothing.

DD.20121104.1500.CET

Are you sure you're talking about the tag-filename converter?

The conversion string is entered manually, or else chosen from a drop-down list of past strings that you entered manually. There is no pick-list of field names provided.