As of now Sumatra shows only 9 files in "Favourites" main menu and only 10 favourite pages in main sub-menu for the specific file. That is very inconvenient and it forces to open side-menu of my favourites every time I start the application.

If it's not possible to remove limits then I suggest add such option in the ini-file for more customization. For example, to rise the limit from 9 and 10 to 90 and 100 and so on.