This plugin is made to emuate the old R-key repeat function of earlier Sibelius versions. It is intended to repeat the selected note but to truncate it if it's duration would cross a barline.
For multiple selections, just use the regular repeat function in Sibelius (since the old repeat function worked the same with a multiple selection).
Best when assigned a shortcut to (since this is often called the 'Old R-behavior). It works for all notes, chords, and rests. But, as mentioned it i intended for a single selected note, since this was the only instance in which the old repeat function was different.