Answer
@gman no longer works (using WikiEditor version 0.3.1).
If you are just a wiki editor, you need to uncheck
Enable navigable table of contents
under
My Preferences->Labs features
If you are the owner of the wiki, you must add this line to the LocalSettings.php file:
$wgDefaultUserOptions['usenavigabletoc'] = 0;
This disables the navigation column on the right side of the wiki editor for all users, which seems to be causing the row to malfunction.
source share