Fixed
No more brief flash of the wrong language. When several people were working at the same time and one of them had the interface set to English, a freshly loaded page could appear in the wrong language for a moment and then correct itself. Every page now gets its own language and keeps it.
No more empty headings while loading. Right after an update, or after a longer break, titles and labels sometimes stayed blank for a moment before appearing. The text is there straight away now.