In vector skin sometimes (depending on the width of the browser window) following lines get an additional line break. The exact width when this happens depends on your language, because size of the buttons is language dependent.

First list element is broken:

Menu element is broken:

Should look like:

Steps to reproduce:
You have to have sysop rights to get the extra buttons.
Goto: https://de.wiktionary.org/w/index.php?title=Ansicht&action=history
Change the width of your browser window.