I think it'd be a nice option, but not the default.
The whole point with figures is that they are NOT a piano roll. Segments are kept together for a purpose. So splitting them needs to be expressly what the user wants (if they want it).
I just thought that by cutting a segment or a figure, Synfire would only recalculate the musically logical connection between the figures obtained after the cut
partial copy/cut would also be very appreciated. The following, for example, will copy/cut the entire figure although I do want to cut only the last four segments...
