Fixed #2030: Label text bounding error

As you see from the screenshot above, I'm using the same label, but string wrapping is causing parts of strings to appear in different lines.

The first screenshot has 足りない、 on the second line,
but the second screenshot has 足りない、 on the first line.

Something seems to be going wrong with bounding when strings cross the boundary - this seems like a big bug that needs fixing.

Here are two test strings that might help:
バグ等に思われる物を発見したり、何らかの機能が足りない、
バグ等に思われる物を発見したり、何らかの機能が足りない、aaaaaaaaaaaaaaaaaa