Thank you for your answer.
Yes, "Piano-Roll" = "piano virtuel".
For my part, it's the bazaar, I have not yet found a satisfactory solution.
So I use :
1) the step squencer in the BBEditor for its ease of use which makes it possible to test things quickly,
2) and the piano-roll in both the BBEditor and the SongEditor when I have to get out of the grid, when I want to get finer melodic and rhythmic variations, or when a note exceeds the end of the last measure of the pattern.
With the BBEditor, I mix the three "Philosophies of pattern design" (
https://lmms.io/wiki/index.php?title=Co ... _Sequences) depending on the advantages and disadvantages of each.
But when a project grows, the ergonomic limitations of LMMS are very constraining, in terms of legibility, and thus of ease of writing of a project (project easy to start, more difficult to finalize, at least, for me).