Gtk::Builder::get_widget_derived() Issue on Fedora 33

[ahmet öztürk <bilheps gmail com>]

Hi all,

On Fedora 33, derived widgets does not seem to be constructed properly by Gtk::Builder::get_widget_derived(). The reason I think so is that the overridden methods are not called for these widgets. Apart from that everything seems normal. No error message or anything.

I attached a sample code with a very simple case to replicate this problem. on_button_press_event() is never called for the derived widget.

I have also noticed that if a dummy instance of the derived widget is created separately (using another constructor) before calling Gkt::Builder::add_from_string(), then the widget created by Builder also works normally.

Please note that this may not occur on all distributions. e.g. I know that it does not occur on Arch Linux.

Does anybody know if this a Fedora 33 specific issue or is it due to a recent update in Gtkmm that is only affecting Fedora for now?

Attachment: main.cpp
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