You have declared the TextView as a local variable in the constructor.
It will be deleted when the constructor finishes. You must either
declared it in your window class, like the buttons in
https://gitlab.gnome.org/GNOME/gtkmm-documentation/-/blob/master/examples/book/grid/examplewindow.h
I am trying to add a TextView instance to a Grid. But when I display the
window, it is
empty. The Grid examples I have seen add buttons to the grid and these work
fine
for me. But I don't understand the difference between adding a button and
adding
a TextView. If anyone can help me with this, I
