This is needed for the glade integration of CSD windows.
c5c21bb GtkWindow: Add a getter for the custom titlebar
docs/reference/gtk/gtk3-sections.txt | 1 +
gtk/gtkwindow.c | 25 +++++++++++++++++++++++++
gtk/gtkwindow.h | 2 ++
3 files changed, 28 insertions(+)
Upstream: git.gnome.org