Oops, forgot to mute the grace notes.
!NoteWorthyComposerClip(2.0,Single)
|Note|Dur:8th,Triplet=First,Slur|Pos:4|Opts:Stem=Up,Slur=Upward,Beam=First
|Note|Dur:64th,Grace|Pos:14|Opts:Stem=Down,Muted|Visibility:Never
|Note|Dur:8th,Triplet,Slur|Pos:3|Opts:Stem=Up,Slur=Upward,Beam
|Note|Dur:64th,Grace|Pos:13|Opts:Stem=Down,Muted|Visibility:Never
|Note|Dur:8th,Triplet=End|Pos:2|Opts:Stem=Up,Beam=End
!NoteWorthyComposerClip-End
This sample printed very nicely for me. You might want to have the grace notes stems up (if - say - it's the soprano line and everything is stem up), in which case the grace notes would need to be repositioned.