some tags cant coexist, while others can.
for example, for mochi, only one of the following types of tag can be selected at a time: author, keyword, category, rating. but, until clicking into one of them all possible ones are shown, and you can have one of each type selected.
Once you get to the end of the importable list (unfortunately, unable to determine an endpoint before you get to it) if you click the provided go back button, it should put you back on the last page with the last active tags, but if you start over completely with import, it does not remember the tags you chose, because they are method specific.