The problem with disappearing menu

Hello
I want to thank you for creating a beautiful pattern. Made based on it’s school. But there is one problem - the menu. The menu is very quickly disappears when you hover. Have to click on the name of each menu to “hold” it. Here is my site http://school39irk.ru/, can see how responsive menu. Please advise what to do? Very awkward to operate.
Sincerely,
Oleg

This bug was fixed several months ago which means that you are using completely outdated version of this theme. I strongly recommend to update to the latest version.

Otherwise you can fix this issues by moving sub-meny slightly up like this

#main-nav ul li ul {
	top: 40px;
}

Add this code to Theme Options - Other - Custom CSS

Thanks for the advice. I’m new to this. And how you can update the theme? I will not lose data?

You won’t lose any data and customization done via Theme Options such as Custom CSS, social media icons, slider settings etc but you will lose changed you have made directly inside code. However, this can be avoided by using Child Theme in first place You can read more about child themes here: Child Themes « WordPress Codex

You don’t see update notification inside your Wordpress dashboard because you have changed theme version in style.css, so automated updates no longer work.

If you did make changes directly inside code, then it is better not to update as all those changes will be gone. But keep in mind for other WordPress websites. Also you won’t receive any new features and bug fixes (like you already needed)