HI,
The issue is with the way you setup the "post code" field of your tax rule. You can't give a list of post codes like you did.
Please read the documentation on how to setup that field:
Post code : You can enter a regular expression matching the post codes you want for the current tax rule.
For example, if you want that the current tax rule apply to all the people with a post code between 12000 and 12999, you would enter such text in the field: 12[0-9]{3}
The brackets indicates the list of potential characters (ie. 0,1,2,3,4,5,6,7,8,9) and the curly brackets indicates the number of characters for the characters in the brackets.
Another example would be all the zip codes from 12546 to 12549 and you would enter: 1254[6789]{1}
That means that you'll want to create one tax rule for each range of post codes.
PS: the cumulative tax icon was not meant to be toggable so it's not really a bug. But yes, it could be nice to make it toggable.