With this commit, it is possible to use
This is related to https://bugzilla.gnome.org/show_bug.cgi?id=734033
14eccae GtkWindow: Add a way to declare initial focus in ui files
gtk/gtkwindow.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 80 insertions(+), 15 deletions(-)
Upstream: git.gnome.org