As you can see in attachment, probably we need a little more space (3 pixel?) between window border and first left letters (top, bottom, right too??). This isn't a font trouble, but text_widget's settings one. BTW: using a no-monospace font you can have some trouble with plain-text-formatted-or-aligned files, like: +--->leaf 1 | +----+-->leaf 2.1 | +----->leaf 2.2
Attachment:
Schermata-Nautilus.png
Description: PNG image