How to implement a dialog box for quick editing?

Question

CMS

Hello
In my CMS, I am making it possible to quickly edit content from the site. When you hover over an element, the edit button appears, then a dialog box opens:

What is the best way to display the contents of the window: load via ajax or iframe?
The downside of loading via ajax is that js and css of the site can intersect with the contents of the window.
The option with iframe with js, css is simpler, there can be no intersections with the site.
Now I'm using ajax.
Which option is better to use?