Only define filter variables that are not default values.

Up to you really, but it would be good to have a clear cut rule and not re-state the default.  Or just leave as is and just use the guideline of a valid filter.  I just feel we don't want to be somewhere in between for a small change like this.

This could be just having two ways to specify the filter simple vs. advanced, rather than a bug.  So it may be an inconsistency.  I haven't checked though.