Chat Box / Commands - When Trying to Delete letters, it deletes the whole word instead.

During my testings with the new commands, I noticed something unusual. Every time I misspell a command and try to fix it by deleting a letter, it deletes the whole word instead. This also applies for non-command text, like "Hello".
From what I know, there isn't any thing particular that effects this bug. I've also tried logging out, and logging back into the world, but the bug is still there.

Example of the what the chat box looks like.

Misspells command:
<takatino> /tp @p 100 100 100p

Hits "Delete" key once, and results in:
<takatino> /tp @p 100 100