Dorro1971, Is there a way to connect with you directly? I'm on IG as gerrit1857 if that helps. It works for me, although the process once you get Glade operational is shall we say quite obtuse. The whole thing makes me glad I (used to) develop on Windows.
Dorro1971, as vmax549 was reminded of recently, you need to install gtkscourceview2.0-dev package in order for Glade-gtk2 to see the widget. Without the widget, Glade will delete anything gtksourceview realted out of the .glade file on Save. Which of course results in PP not loading it.