Sometimes GTK modal dialogs are not modal — bug or feature?
Definitely a bug. Post a bug report and/or upgrade your GTK+ lib.
gtk
What is the relation between GTK, GTK+ and GTK2?
The first incarnation of the project was called GTK (which stood for GIMP Toolkit). At some very early point, while the project was still part of The GIMP (and before version 1.0), it was renamed to GTK+. Despite this, people often referred to it as GTK out of convenience or ignorance. The GTK+ name was … Read more
GtkDialog mapped without a transient parent
You fix this warning by giving the GtkDialog a parent to be modal to. The relevant functions are gtk_window_set_transient_for() (which sets this window to always be on top of, or transient for, another one) and optionally gtk_window_set_modal() to make it a modal dialog. This is ultimately what the various GtkDialog constructors do.
GLib compile error (ffi.h), but libffi is installed
If you have a Debian-based Linux OS with apt-get: sudo apt-get install libffi-dev With a Redhat-base OS: yum install libffi-devel With Alpine Linux: apk add libffi-dev