Hi @Pbalazs89,
Thanks for reaching out.
It’s not a page size issue, that’s why it also happens on the localhost. It’s the processing speed of the server (either localhost server or actual server) and the rendering speed of the device. And it’s unavoidable as the content grows, depending on how many executing codes are there (HTML, CSS, Javascript). The only solution I can recommend is reducing the content and split it into multiple pages.
It also happens on other plugins and or Wordpress features when it became too long that the browser has having hard time to process. Example, install Ubermenu and go to Admin > Appearance > Menus and add hundred of menu items, and reload that same menu page, and it’s going to be painfully slow too
. I only use Ubermenu as a sample to dramatically increase the items feature so we don’t have to add thousands of items just to reproduce it.
Thanks!