Breakdown of Форматирование то и дело меняется.
Questions & Answers about Форматирование то и дело меняется.
Because форматирование is the subject of the sentence: it is the thing that changes.
- форматирование = formatting
- меняется = changes / is changing
So форматирование stays in the nominative singular.
If you changed the sentence so that formatting was the object, the case would change. But in Форматирование то и дело меняется, it is the thing doing the changing, so nominative is exactly what you expect.
То и дело is a fixed idiomatic expression. It does not mean something like that and business if translated word-for-word. As a whole, it means:
- constantly
- again and again
- every now and then
- keeps ...-ing
The exact English translation depends on context.
In this sentence, it suggests repeated change, often in a slightly annoying or noticeable way:
- Форматирование то и дело меняется.
- The formatting keeps changing.
So it is best learned as a chunk: то и дело.