How to quickly change the left and right margin of individual system?

Dear advanced users and developers,

How could be the left and right margin of individual systems quickly changed?
I press alt + arrow or alt + shft+ arrow, but they are extremely slow.

Thanks in advance!

Probably best using a separate Music Frame.

Thank you for your quick and accurate answer.
I think, however, that inserting separate music frames make the order of the bars in the same frame confusing…
I only need some bars on the page of the legend which is inserted between the instrumentation of the piece and the score (and parts).

Did you try Ctrl-Alt-right/left arrow? That moves items by larger increments than Alt-arrow (and also Alt-Shift-arrow I believe)

I am using Catalina and cmd+alt+arrow is better. However, it is still too slow.

If this is a legend on an instrumentation page, the obvious solution is to change the width of the music frame (and it should probably be a layout frame that references a separate flow to what follows on the first page of music).

If this is real music, midway through a flow, then shrinking it rarely makes musical sense.

If this is an entire flow or the very end of a flow, there’s a layout option to only justify the final system when a certain horizontal threshold is met.

For moving the left and right edges of a system there is no quicker way than the way you’ve found. In general practice there’s very rarely any need to use that method, though.

If this system is in the middle of a page, you could give that page 3 frames: the top and bottom ones being full-width, the middle one being smaller. Make sure they’re all set to the same frame chain, in the order 1-2-3 down the page, and it should all work correctly. You might need to use system/frame breaks to make sure material appears in the desired frame.

Thank you for your kind and friendly answers.
I have still some Finale-behaviours… I will try to add music frame correctly… Probably I misunderstood something.