It is easy way to correct lesson's title?

No/Yes (explain, please)
p.s. must be: Is there any easy way… (sorry… rush)

After you open a lesson, click on the menu (hamburger) button on the top left and there you will find “Edit Lesson” option. On the Edit Lesson page you can change both lesson title and text.

The text is editable but not the Title. There are no button, links, or anything to edit the Title.

yeah. it still doesn’t work.
as I told, it is a bit difficult when you import book and when you have a lot of books in your curses and it looks like in the vocabulary you have a lot of lessons like Part 1, something like that. Hope you understand what I mean. It is hard to find in vocabulary lesson you want.
It also will help if when book imported and parts title not to be “part 1”, but will be like title of the book “Foundation part 1 and etc.”

have you clicked in the title text and started typing?

Yeah, I have tried it.
I does not work. It opens lesson and you must change title.
You cant change title without open lesson.