With parallel installation of Master "LOdev 3.6.0alpha0+
– WIN7 Home Premium (64bit) ENGLISH UI [Build ID: 4495824-6299bf6-ec8645]"
(tinderbox: Win-x86@6-fast pull time 2012-04-08 00:03:52) I see a completely reworked dialog without the known button. May be come day users will accept new design being outclassing the simple button, but it's not a good idea to force users to read help how to use the new dialog instead of simply leaving the button for a while in the dialog.
Screenshot here: <https://bugs.freedesktop.org/attachment.cgi?id=59663>
"Default Directory" button was intentionally removed, because it is in the Places.