A swing style needs triplet resolution to swing the melody. Rather than show every pair of eighth notes as triplets, sheet music is usually shown with even eighth notes and some form of instruction given to the reader to play the music as 'swing'. BIAB doesn't provide this instruction.

My keyboard player has a real problem with this, such that we now pencil in this notification, otherwise he plays it straight. The style name can sometimes tell you it is swing, but not always.

I can't tell from your original message if you want even eighths or swing eighths in your melody. But before you enter it, you can immediately see if the melody is swing or even. Each note has 4 lines in even and 3 in swing. This is defined in the style. When building a new style you have to check a box to identify if you want a JAZZ (ie swing / triplet) style.

BIAB for Windows Version 2019 (643)
Windows 10 (1909)