I have noticed that the multi-note tremolo option does not work when either note is tied. This an issue with dotted crotchets in 4/4 where one is forced tie over the half bar. Can someone tell me how to fix this?
Enter your note(s) using force duration to use dotted notes.
Derrek is right, in order to show multi-note tremolos, notes have to be notated using a single notehead (rather than 2+ tied notes).
And welcome to the forum @Delphi_Apollo !