Under ubuntu 16.04 I get the following message
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged
when I open zenity with the command
zenity --text-info --filename=<filename>
This didn't happen under 14.04. I presume that the answer is related to this post but the post doesn't explain how to implement the proposed solution. Could somebody please explain which file I should add the suggested lines to?
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.