Locating xpath not work with html tags browser or window

Hi all,

I m trying to set by import an authorities certificat in my firefox. When i look at the DOM, i can see the element of the import popup, but when i try to found and click on differents buttons : Not Found !
In fact, by RobotFramework, the source (i made a “get source”) stopped at the html tag / juste like it’s a frame.
I can see and test visibility of <browser class=“dialogFrame”…, but all tags behind are unreachables…

If you want to see the window code :
about:preference#privacy + View certicates button
Make a F12, inspect the Authorities Tab.

To have access, I think i must to do an action like “Select Frame” on this tag but i not found how…
Can you help me please
Thx a lot