Make the header bar floating over the content

[marbetschar]

If possible, so we gain the red marked height and the app itself occupies less space on the screen:

[marbetschar]

Seems like Hdy.ApplicationWindow has no separate titlebar and one is expected to pack a headerbar inside. So we may gain this height by switching to libhandy.

To keep in mind: libhandy is only available on Odin.

Source: https://developer.puri.sm/projects/libhandy/unstable/HdyApplicationWindow.html

[marbetschar]

• "HdyWindow allows to ... show titlebar above content by putting it into a GtkOverlay instead of GtkBox ..."
• "HdyApplicationWindow is a GtkApplicationWindow subclass providing the same features as HdyWindow."

https://gnome.pages.gitlab.gnome.org/libhandy/HdyWindow.html

[hanaral]

Unless the headerbar is Gala territory, can't you overlay the content over the headerbar?