Comment 18 for bug 1788495

@Jeff-

Yes, the tree scrolls horizontally as well as vertically. I'd love to figure out the autosizing on GTK generically as it doesn't work for grids as well as treeviews. Haven't dug into it much but I imagine we'll need to overload and call something to calculate a character width from the system. That would catch the extra large fonts on GTK as well. On the Mac, it seems less of an issue as they don't allow changing font size independent of screen resolution (at least as far as I can tell in the standard system settings)