Note back to unread

When I’m filing a note from my inbox to an other folder,the status of the concerned note is set back unread mail and is put back in bold.

Do you have a solution to avoid this ?

Thanks

Subject: a few questions / clarifications

How did you file the message? Did you use Folder → Move to Folder?
What was the read/unread status in INBOX before you file it?
Was it the filed message that turned unread?

Thanks.