I recommend that you log out of Wikitree and then log back in. If this doesn't fix it, you might clear your Wikitree cookies.
It is possible that someone was working on that merge when you tried to do it and now that page is in your cookie cache.
For Chrome, click the "secure" left of the url/address at the top of your browser, select cookies and delete Wikitree.com You'll need to log back in and when you refresh, it might go away. Please say if this works or not.