Not resetting the trackers files field prevents additional trackers in a new name file from being reached

All right there in the title. Users wouldn't know to click that dot to reset instead of overwriting the path to the desired trackers file.

No file or test is named in the issue. Start by locating the tracker-file selection and reset behavior, then reproduce the case with a new name file; done means additional trackers are reached without requiring users to discover an undocumented reset action.

索引モデルが issue の本文から書いたものです。