It works here just fine, but when I use modal-full-height modal-left then it doesn't work

Hi!

It works, but I'm afraid that it doesn't affect on every element on your page.

Look - I've made a sample page for you: https://mdbootstrap.com/snippets/jquery/krzysztof-wilk/2040520

When you launch modal, you can use NavBar to navigate between sections on the page. On the bottom you have four buttons for notifications and you can use them even if the modal is opened.

The basic functionality of page is preserved, but, for example, you can't type into inputs when modal is launched.

Modals are made to communicate the user important informations - for example discounts, new version of your products etc. You can use them to get info from user using forms too. So modals are focusing users attention and when modal is launched - work on other parts of your page shouldn't be necessary.

I think everything works correctly :) If you have more questions - just ask, I'll try to help :D