genre tags

can somebody help me with implementing genre tags? For example: I wanted to tag a number of songs as "jazz" in the hope that when I chose "Open Lyric" in LyricPad I *should* then have been able to click on the wee button on the right that gives access to the "Genre Submenu". This is what I tried: in each of the song files I considered to be jazz, I inserted a 'genre tag' at the top of the file like so

@!genre jazz
EVERY TIME WE SAY GOODBYE Cole Porter

every time we say goodbye, I die a little
every time we say goodbye, I wonder why a little
... [etc]

I edited and saved each of the 'jazz' files on my Windows computer, then uploaded all of them to the LyricPad folder on my Android tablet while LyricPad was not open. I then opened LyricPad, went to "Open Lyric" and clicked on the wee button on the right which then allowed me to choose 'Genre Submenu'. My collection of tagged (so I thought) jazz songs didn't appear: the LyricPad message at the top of the page saying simply "Unknown - 171 files". What am I doing wrong?

Solved: I rebooted the tablet. I can now see the 'genre submenu'(s). All good.