When managing permissions, Liferay doesn't persist your choices if you navigate away from the page. You have to click save each time if you want to add permissions that are on different pages.
Steps to Reproduce
1. Go to any Site -> Content -> Web Content.
2. Create a web content
3. Click on the three dots and click on Permissions
4. Scroll all the way to the bottom and change the delta from 20 Entries to 5, so you can have pagination.
5. Check any permission boxes for any role, it doesn't matter.
6. Go to the next page of roles
7. Go back to the first page.
Result: You'll see that the permissions you selected in Step 5 are not checked anymore
Expected: The boxes retain their checks from Step 5.
This is a feature request to have Liferay retain the checks from page to page so you don't have to click on Save for each page.