Dear chengjm,
Pardon me if this looks bold, but we’re dealing with Dorico’s voices system for over a year now, and it does work perfectly once you “learn” how to use them. So maybe, instead of trying to make the system work as you wish it would, you might try to work with it the way it’s designed to be… You’ll earn time, I guarantee!
Use voices colors when dealing with complicated staved, be really careful with the little reminders on the cqret, and use the “change voice to…” with the right click any time you feel the need for it 
But don’t try to make us ALL change the workflow, unless there really is a major failure and you have an answer.
FWIW, reading again you previous post, I know what has upset me : when I enter notes on piano staves and create a new voice, I DO NOT have all my previous notes go wrong. Actually it does not change anything — well, of course, it could change the stem direction, accordingly to the type of voice I add, but this is all under MY control.
You might need to be more specific on that field, because I think I misunderstood your real problem.