I did an update to MW 1.18 and now I have a problem with the search suggestions:
The suggestions appear and when I click one, the text is filled into the search box.
However, the form is not submitted. So the according page is not loaded anymore. This worked correctly in MW 1.17.
I can reproduce this bug with several skins: With Vector and with MonoBook and with a custom skin, which is based in Vector.
I have tested the following browser:
The issue is present in FF8 and FF9.
It is not present in IE8, Opera and Chrome.