Furigana breaks when dashes or hyphens are used

Question

Furigana doesn't work when there's a dash or hyphen in it:

てんぷらや{tempura-ya}

てんぷらや{tempura-ya}

てんぷらや{tempura-ya}

てんぷらや{tempura-ya}

but works when there's no dash or hyphen:

てんぷらや{tempuraya}

てんぷらや{tempuraya}

Is this accidental, or by design?

While I realize that the dashes and hyphens only occur in Romaji, knowing how words are constructed (eg -san, o-/go-) can be useful in understanding the language.

Answer 1

You should enclose the parent of ruby (てんぷらや in this case) by brackets ([]): [てんぷらや]{tempura-ya}. You can omit brackets in some cases, but not always.