Text editing control misbehaves near line end

If you try to edit the text of your message in the Whisper window or Mail composing window and the text caret runs over the end of line the text you type will be inserted in the reverse order.

E.g. type in the Whisper window:
test message to check if this bug
reproes

Then place the cursor after "bug" an try to add " still".

Expected:
test message to check if this bug
still reproes

Observed:
test message to check if this bug
llits repros