'Search box' doesn't work in the library

Today I wanted to find some lessons that I know they are in the library but instead of turning over the pages I tried to find them by using the search box.
But after the first typed letter in the box, the system answered that nothing was found!
I tried several times, but in vain!
Maybe it would be better to have a search box for typing and near it the bottom to press for searching after we’ve finished to type the name of the lesson?..

@evgueny40 - The search tries to search as you type. Keep typing the rest of the word you are searching for. You don’t have to stop typing when it starts searching.