Is it possible, in the current version, to have a 2-3 bar on one line as short as necessary like the joined example?
it is for a music theory document that will need 30 or more of those short bars each followed by a 20-30 bars musical example.
In Setup mode, go to the Setup / Layout Options menu.
On the Note Spacing page there is an option “only justify final system when more than … % full”.
You might also need to make a different flow for each “short” and “long” example, and choose “Allow new flows to start on existing page” in the Page Setup page.
Or you could create frames with a narrow width (maybe all the same narrow width) and justify the “short” examples in those frames.
Too many options … 
Rob
this is good news but
In Setup mode, go to the Setup / Layout Options menu.
On the Note Spacing page there is an option “only justify final system when more than … % full”.
couldn’t make it work this way the option doesn’t change anything. Isn’t it only for final systems ?
Yes, but it works on the final system of each flow in the layout. You could create each 3-bar snippet and the longer example that follows it as a separate flow.
It comes from an xml import from S. where all this was very easy to do with the bar handles.
well it can wait.
thanks for your help