I am currently using the latest Windows version of SeeMusic (3.9).
When typing the bar lines opacity value that is greater than "2", the value will be set to "2". For example, when I type "1.5" into the opacity value field and press Enter, the opacity is set to "1.5", but when I type "10" into the opacity value field and press Enter, the opacity is set to "2" instead of "10.
Besides, the bar lines continue to show up even though the song (MIDI track) has ended.
The Bar Lines showing up after the ending will be fixed in Version 6.0.3, available in next 24 - 72 hours.