Setting it as model root path in DirectoryView::setup_model() for
windowed mode as well would cause an issue with the following:
- "open ~/Desktop"
- "FileManager ~/Desktop"
- "Show in FileManager..." from Desktop context menu
When viewing the Desktop as the initial path it would be the same and
on_path_change wasn't called, leading to various widgets and window
properties not being updated.
Fixes#3772.
20907780bd