In 1.1.0.9, the client now sends BlockEntityDataPacket to the server for every change they make to a sign while typing on it. This means that users can see what other players are typing on a sign as they are writing it. OK so far.

However, this is an issue for custom servers in that we cannot detect when a client closes the sign GUI. This is a problem for plugins listening for sign text changes because we have no way of telling if the sign text is finalised. Previously the text was only sent when the client closes the sign GUI.

As per shoghicp's suggestion, I also add that this kind of behaviour also potentially allows modified clients to change sign text, as because the text may now change multiple times, the server won't disallow changes to the sign text by other users.

References:

• https://github.com/pmmp/PocketMine-MP/issues/956