Perhaps the bug is in the core javascript, but since WikiEditor is the only component I can test this bug on I report it here:
To reproduce open any page for editing in a skin other than vector (tested: monobook, modern, simple). Click on the link dialog icon and enter anything in the textbox.
Firefox shows a javascript error:
$autoEllipseMe.autoEllipsis is not a function
Version: unspecified
Severity: normal