Just to demonstrate the capability, not because this is excellent UI.
1fb154e gtk3-demo: Add a scrollbar context menu
demos/gtk-demo/main.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
demos/gtk-demo/main.ui | 2 +-
2 files changed, 49 insertions(+), 1 deletion(-)
Upstream: git.gnome.org