Unable to capture mouse events of GtkGLArea

[Johannes Bauer <dfnsonfsduifb gmx de>]

Hey list,

I'm writing a small toy application that uses OpenGL. Actually
converting it from GLUT to GTK/GL. I'm using a glade 3.22.1 generated UI
with Gtk 3.22.30 from Python3.

I'm having two issues: The more pressing one is that I cannot seem to
figure out how to capute mouse events on my GtkGLArea. I've tried a
bunch of different settings, enabled all events, played with can
focus/can default/receives default and hooked button-press-event,
drag-begin, enter-notify-event, event, key-press-event,
motion-notify-event, etc -- none of which fire. They seem to be caught
by the main window (I testwise hooked those for the main window). But I
want to receive coordinates relative to the GL drawing area (obviously),
but don't know what I'm doing wrong. The hierarchy is GtkWindow ->
GtkBox -> GTKGLArea (if that matters). Any advice on how to set this up?

Another question related to the GtkGLArea is that I would like to create
a pixmap copy of a rendered image (to be able to save it as PNG, for
example) -- is that at all possible?

And thirdly (and completely independent), is it possible to have the
rendered text of a GtkScale use markup? I want to show
"10<sup>%.1f</sup>", but it only shows up as literal text, not
interpreting the markup.

Thanks for helping out!
All the best,
Joe