Fatal error: OOUI\Exception: OOUI\Theme::singleton was called with no singleton theme set. in /web/htdocs/www.tempodiriforma.it/home/mw/vendor/oojs/oojs-ui/php/Theme.php:31
Stack trace:
#0 /web/htdocs/www.tempodiriforma.it/home/mw/vendor/oojs/oojs-ui/php/Element.php(259): OOUI\Theme::singleton()
#1 /web/htdocs/www.tempodiriforma.it/home/mw/vendor/oojs/oojs-ui/php/Tag.php(507): OOUI\Element->toString()
#2 /web/htdocs/www.tempodiriforma.it/home/mw/extensions/VisualEditor/includes/Hooks.php(244): OOUI\Tag->__toString()
#3 /web/htdocs/www.tempodiriforma.it/home/mw/includes/HookContainer/HookContainer.php(161): MediaWiki\Extension\VisualEditor\Hooks->onTextSlotDiffRendererTablePrefix()
#4 /web/htdocs/www.tempodiriforma.it/home/mw/includes/HookContainer/HookRunner.php(1332): MediaWiki\HookContainer\HookContainer->run()
#5 /web/htdocs/www.tempodiriforma.it/home/mw/includes/diff/TextSlotDiffRenderer.php(273): MediaWiki\HookContainer\HookRunner->onTextSlotDiffRendererTablePrefix()
#6 /web/htdocs/www.tempodiriforma.it/home/mw/includes/diff/DifferenceEngine.php(942): TextSlotDiffRenderer->getTablePrefix()
#7 /web/htdocs/www.tempodiriforma.it/home/mw/includes/diff/DifferenceEngine.php(928): DifferenceEngine->showTablePrefixes()
#8 /web/htdocs/www.tempodiriforma.it/home/mw/includes/page/Article.php(979): DifferenceEngine->showDiffPage()
#9 /web/htdocs/www.tempodiriforma.it/home/mw/includes/page/Article.php(490): Article->showDiffPage()
#10 /web/htdocs/www.tempodiriforma.it/home/mw/includes/actions/ViewAction.php(78): Article->view()
#11 /web/htdocs/www.tempodiriforma.it/home/mw/includes/MediaWiki.php(583): ViewAction->show()
#12 /web/htdocs/www.tempodiriforma.it/home/mw/includes/MediaWiki.php(363): MediaWiki->performAction()
#13 /web/htdocs/www.tempodiriforma.it/home/mw/includes/MediaWiki.php(960): MediaWiki->performRequest()
#14 /web/htdocs/www.tempodiriforma.it/home/mw/includes/MediaWiki.php(613): MediaWiki->main()
#15 /web/htdocs/www.tempodiriforma.it/home/mw/index.php(50): MediaWiki->run()
#16 /web/htdocs/www.tempodiriforma.it/home/mw/index.php(46): wfIndexMain()
#17 {main} in /web/htdocs/www.tempodiriforma.it/home/mw/vendor/oojs/oojs-ui/php/Tag.php on line 509