Won't let user type more than two lines of a sign before freezing.

In windows 10 edition, there is a problem with the signs. It lets you place down the signs and lets you type at least a couple of lines out, but anything above two lines just makes the game kinda freeze. The background moves fine, things continue with that, it's just with the sign itself. It won't let you type out any more words or letters, and it won't let you get off the sign, even when you click away or press esc, a few times. After a few minutes after pressing buttons, etc, it finally lets you off the sign with what it let you type, still on there.