Hi, this is using Cambalache 0.10.3 on Guix System (guix 77e768a). The problem seems limited to GTK 4 projects. GTK 3 worked for me. STEPS TO REPRODUCE 1. Launch Cambalache 2. Create a new GTK 4 project 2.1. Click "Create a new project" button 2.3. Add project name (e.g. test) 2.4. Choose location 2.5. Select Gtk 4 as Toolkit target 2.6. Add UI file name (e.g. window.ui) 2.7. Click "Create" button EXPECTED RESULT ☑ The workspace is loaded ☑ Clicking Toplevel → GtkApplicationWindow add a new app window to the workspace UNEXPECTED RESULT ☒ The workspace loads with an error: ~~~ Workspace process error Stopping auto restart ~~~ ☒ I can't add any GUI component to the workspace. Clicking Toplevel → GtkApplicationWindow adds the window to the project tree but not to the workspace ADDITIONAL INFORMATION Starting Cambalache from a terminal and following the steps to reproduce I can see the following error: ~~~ LANG=C cambalache ** (process:18718): WARNING **: 08:08:13.250: Failed to load shared library '/gnu/store/zhax2b3av3cr8nfhhl5fjacj4ayn1xcb-gtk-4.8.0/lib/libgtk-4.so.1' referenced by the typelib: libgtk-4.so.1: cannot open shared object file: No such file or directory Traceback (most recent call last): File "/gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/merengue", line 47, in from merengue import MrgApplication File "/gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/__init__.py", line 43, in from .mrg_application import MrgApplication File "/gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/mrg_application.py", line 30, in from gi.repository import GLib, GObject, Gio, Gdk, Gtk File "", line 1007, in _find_and_load File "", line 986, in _find_and_load_unlocked File "", line 664, in _load_unlocked File "", line 627, in _load_backward_compatible File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/importer.py", line 145, in load_module dynamic_module = load_overrides(introspection_module) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/overrides/__init__.py", line 118, in load_overrides override_mod = importlib.import_module(override_package_name) File "/gnu/store/qar3sks5fwzm91bl3d3ngyrvxs7ipj5z-python-3.9.9/lib/python3.9/importlib/__init__.py", line 127, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/overrides/Gtk.py", line 111, in class Widget(Gtk.Widget): File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/module.py", line 168, in __getattr__ interfaces = tuple(interface for interface in get_interfaces_for_object(info) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/module.py", line 94, in get_interfaces_for_object interfaces.append(getattr(module, name)) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/overrides/__init__.py", line 32, in __getattr__ return getattr(self._introspection_module, name) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/module.py", line 207, in __getattr__ wrapper = metaclass(name, bases, dict_) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/types.py", line 247, in __init__ register_interface_info(cls.__info__.get_g_type()) TypeError: must be an interface WARNING:cambalache.cmb_view Error stoping /gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/merengue [Errno 3] No such process ** (process:18729): WARNING **: 08:08:13.405: Failed to load shared library '/gnu/store/zhax2b3av3cr8nfhhl5fjacj4ayn1xcb-gtk-4.8.0/lib/libgtk-4.so.1' referenced by the typelib: libgtk-4.so.1: cannot open shared object file: No such file or directory Traceback (most recent call last): File "/gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/merengue", line 47, in from merengue import MrgApplication File "/gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/__init__.py", line 43, in from .mrg_application import MrgApplication File "/gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/mrg_application.py", line 30, in from gi.repository import GLib, GObject, Gio, Gdk, Gtk File "", line 1007, in _find_and_load File "", line 986, in _find_and_load_unlocked File "", line 664, in _load_unlocked File "", line 627, in _load_backward_compatible File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/importer.py", line 145, in load_module dynamic_module = load_overrides(introspection_module) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/overrides/__init__.py", line 118, in load_overrides override_mod = importlib.import_module(override_package_name) File "/gnu/store/qar3sks5fwzm91bl3d3ngyrvxs7ipj5z-python-3.9.9/lib/python3.9/importlib/__init__.py", line 127, in import_module return _bootstrap._gcd_import(name[level:], package, level) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/overrides/Gtk.py", line 111, in class Widget(Gtk.Widget): File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/module.py", line 168, in __getattr__ interfaces = tuple(interface for interface in get_interfaces_for_object(info) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/module.py", line 94, in get_interfaces_for_object interfaces.append(getattr(module, name)) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/overrides/__init__.py", line 32, in __getattr__ return getattr(self._introspection_module, name) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/module.py", line 207, in __getattr__ wrapper = metaclass(name, bases, dict_) File "/gnu/store/b07y8a2axslnz97pjdg7lp73xwk1gf8w-python-pygobject-3.40.1/lib/python3.9/site-packages/gi/types.py", line 247, in __init__ register_interface_info(cls.__info__.get_g_type()) TypeError: must be an interface WARNING:cambalache.cmb_view Error stoping /gnu/store/r69vjhbz1vjjaij5wp3nvwvc4czk0pj9-cambalache-0.10.3/lib/python3.9/site-packages/cambalache/priv/merengue/merengue [Errno 3] No such process ~~~ --- Luis Felipe López Acevedo https://luis-felipe.gitlab.io/