I two captions long enough to require two lines on the table index. One of them was break by LaTeX, the other just send an overfull warning and go out of the page margins.
I want '2' to look like '1'. ¿How can I achieve that?. I'm not providing code, I don't think it would be of some help.
You should add all possible places of hyphenation after the period in the problematic word, which means that in the title of 3.5 you should write synch.en\-abled. It may not help (we cannot verify it without the source), but a good behaviour is probable. If not, think about using additionally the microtype package.
\-shows the possible place of hyphenation without forcing it. – Przemysław Scherwentke Aug 23 '15 at 00:47syn\-ch\_enabled. Thanks! – lcjury Aug 23 '15 at 00:48