Hi,
First of all, thanks for the great program!!! 
I have a media size library around 1500 albums, ~15000 songs. All the songs are tagged. Many songs have multiple GENRE tags.
For example, a english pop album I will use 2 genres
Western
Pop
Now, I want to add more GENRE tags to some albums. Such as for a album already tagged as:
Japanese
Jazz
I want to add a third GENRE so the album has 3 GENRE tags:
Japanese
Jazz
Christmas
I did some research and tried some "Action" but couldn't get the result.
My need is to simply add an extra GENRE tag to a list of songs/albums.
I tried "Action -> Replace", but that seems not support wildcard or I simply don't knwo how to do it!
Tried "Action -> Replace with regular expression". I figured ^(.+)$ will match the whole existing GENRE string, then replace with $1\\extragenre But this operation will add extragenre to all existing GENRE tags, meaning on a existing GENRE tag Japanese\\Jazz, it will become Japanese\\Christmas\\Jazz\\Christmas.
Tried "Action -> Format value", and format the GENRE tag to %GENRE%\\extragenre. But the result is the opposite of the above method. This "Format value" will destroy existing multiple GENRE tags, and only take the first GENRE tag and add the extra GENRE. Meaning a existing Genre tag Japanese\\Jazz will become Japanese\\Christmas, instead of Japanese\\Jazz\\Christmas!!!
So, any simple way to add an extra GENRE tag on top of an existing multiple GENRE tags?
Thanks in advance!