make inserting child behaviors simpler

[hollandjg]

from @zzaydin

Having to choose the parent for add behavior might be confusing for the participant
Maybe when you're trying to move something the sequences shouldn't be numbered at all

[jashlu]

Do we not want to have the ability to move sequences?

[hollandjg]

Do we not want to have the ability to move sequences?
I think we do need to be able to move the sequences, just like every other behavior.

[jashlu]

Not sure what Maybe when you're trying to move something the sequences shouldn't be numbered at all means then