When I go to Special:Preferences, tab "Додатки" ("Gadgets"), I can check and uncheck enabling of gadgets but when I click "Save", it restores to the previous state.
I think it should be some configuration issue, as generally I've never encountered similar issues on other Wikimedia projects.
http://uk.wikisource.org/wiki/Special:Preferences#mw-prefsection-gadgets
Version: 1.22.0
Severity: critical