DanielRios549 There is no "blank option" for songs themes, every song displays the first global theme, even if it is not associated with it.
milon @DanielRios549 there is a bug in OpenLP 2.4.5 that makes it so when you Edit a song, if no theme was selected for that song, then OpenLP assigns the first theme from the alphabetical list (ie. if Blue Burst is the first theme in the list, it'll get auto-applied when you edit a song). To correct that for now, edit the song and go to the Theme tab, then choose the theme you would like to use. It's a pain for now, especially if you change themes often, but I think it'll be fixed in the next update. (https://bugs.launchpad.net/openlp/+bug/1666006)
milon Oops! I just realized that version 2.4.6 came out last month. That bug may be fixed already! Time for me to backup my data and do an update. :)
DanielRios549 @milon You are right, the first Theme is automatically associate to the song, not the default, therefore, I always use a global theme for "fix" this bug, I think this is the better solution.