Access to the "standard filter" (which is rather an overview of the current setup) is possible from the autofilter overlay widget or via menu: data > more filters > standard filter.
The dialog has no means to remove rows. So when you want to configure the filter it cannot be done here (although it is possible to add more filters). Likely the row is not applied when field name is "-none-". I suggest to add buttons to add new and delete exisiting filters.
Adding delete buttons at the end of each row should be straight forward and having the clicking of the delete button simply move the content in the below entries up 1 row should also be simple.
The glade UI file is here is at core/sc/uiconfig/scalc/ui/standardfilterdialog.ui and i think the code to run it is in core/sc/source/ui/dbgui/filtdlg.cxx
The way to clear any filter row with the rows below, is selecting -none- for field in the row.
Selecting -none- for the first clear the whole filter.
But it's really an obscure way, and not possible to delete only one filter in middle.
What could be helpful:
+ / - to insert / delete a filter row
˄ / ˅ to move up / down
It's always bad usability to include "none" into lists.
Moving items would be relevant only for OR combinations (which IMHO should be killed with fire). It clutters too much.
I would do it like this (pipe is a splitter, value column client aligned):
[Op] [Field] | [Value]
Foo | 1 [-]
AND Bar | 2 [-]
This seems to have been fixed in 7.1 since:
author Martin van Zijl <email@example.com> Wed May 27 08:21:39 2020 +1200
committer Heiko Tietze <firstname.lastname@example.org> Tue Sep 15 08:40:04 2020 +0200
tdf#76898 standard filter: add buttons to remove conditions
*** This bug has been marked as a duplicate of bug 76898 ***