Putting the preview browser as it is currently created inside of print.html throws some errors and doesn't seem to work. There might be some way to get it inside print.html which would remove the need to modify the TabDialogBox UI and keeps the print preview logic in one place.

I have had a WIP patch for this for a while now (it works but I need to fix the styling of the preview browser, and probably rebase it at this point), but I put it on the back burner as I figured having nightly diverge from beta on this fairly critical point was unhelpful while we were considering releasing the feature in 81, and I wouldn't be all that comfortable with uplifting it.

Now that we're not targeting 81 anymore, I'm looking at this again, but from discussion with Emma around https://phabricator.services.mozilla.com/D88096 I'm not sure we really want to do this? That is, if we need the preview browser and its browsing context for the print process from the native dialog, but want to hide the UI, having the preview browser live inside the dialog UI is going to be problematic...

I thought I needinfo'd Mark for comment #1 but it appears I did not...

Taking this out of my queue given comment #1

(Moving bugs to 86, part 1.)

Moving things to 88, cause we're mostly on Proton these days…

I think we're okay with this being in the dialog itself rather than the dialog frame. Thanks for looking in to it Gijs