However, in /admin/styles/default/adminstyle.css, the a:hover entry comes before a:link and a:visited, so a:hover is not being executed.
This prevents anchor tags (links) from being underlined when you mouse-over them.
To replicate this issue, goto the limesurvey Demo and mouse over any link: Demo.limesurvey.org/admin/admin.php
To fix this issue, you could cut/paste the 'a:link, a:visited' entry from lines 512-515 up to line 41 in adminstyle.css. Then the 'a:link, a:visited' entry would come before the 'a:hover' entry. This would cause anchor tags (links) to be properly underlined when you mouse-over them.