I'm using the Vector skin on the German Wikipedia which currently runs Mediawiki 1.26wmf24 (4a7e100) 00:49, 29. Sep. 2015 and Flagged Revisions (a64d798) 00:44, 22. Sep. 2015.
Using a large font (Ctrl-+ in Chrome) I see a strange effect: the second line at the top of the interface, which contains the functions "Lesen", "Ungesichtete Änderungen", "Bearbeiten" and the search box., keeps moving left and right and up and down, constantly. The rest of the page does not move. The behavior stops as soon as I increase or decrease the font size. The larger font gives a shorter interface line, where the option "Ungesichtete Änderungen" is missing.
The article in questions has unsighted revisions and I don't see the effect on pages without unsighted revisions. So it seems to be an issue of the FlaggedRevs extension and the related interface field "Ungesichtete Änderungen".
I see the effect on Chrome Version 45.0.2454.101 m (64-bit) and Internet Explorer 11.0.23 on Windows 7, but not on Firefox 41.0.
I am attaching three screenshots that were taken on the same page in quick succession.