Text field doesn't scroll back

The bug

When the content of a text box gets shortened, the text doesn't get scrolled back, resulting in a not completely visible text, even if the whole text would fit into the text box.

How to reproduce

1. Write something long into a text box (e.g. chat) so that it goes over the standard width
2. Delete parts at the end until everything would fit into the text field

Also works with going to the beginning, marking everything to the end and pasting something shorter into the text box.
It happens automatically when first choosing "Desert", then "Redstone Ready" in the superflat menu.