This is about the creative inventory search functionality.
Prior to this version, pressing backspace once removed the whole search term if you had picked one or more blocks from the results.

This is no longer the case: Pressing backspace only removes one letter at a time even when I took one of the blocks listed.

(This behavior was introduced to allow for faster searching: The system assumes that the player has found the block/... s/he wanted and clears the complete search field, so that the player can seach for something completely different)