Wikilinks in the format of, [[Washington (U.S. state)|]] are shown as [[Washington (U.S. state)|]] in the preview, instead of [[Washington (U.S. state)|Washington]]. For details of the notation see Help:pipe trick.
Duplicate: Change some link piped to a redirect page to the [[NN (x)|]], format. Press Preview.
OS: Windows Vista
Workaound: Ignore the preview or don't use the pipe trick.