Hi
I recreated one of my site’s headers using header builder manually. I added a search box to the right of the menu, a bit like the one found in your Electron 2 demo. In Google Chrome, the magnifying glass icon displays OK, but in Firefox the icon doesn’t show at all. I think maybe it’s because the icon lines up outside the search box, to the right so is not visible. I came to this conclusion, because in the Electron 2 demo in Firefox, the icon is partially hidden. Your demo has a wider search box than my side. See screenshot below:-
Chrome search: https://prnt.sc/pws1w6
Firefox search: https://prnt.sc/pws2b9
if I then edit the header builder and make the search box much wider, the icon then appears in Firefox:
This tells me that the icon is not properly aligning to the right hand side of the search box in Firefox.
regards
Robert