问题
I would like to add content to the pages of an Assistant window (GtkAssistant) in Glade.
When I add a new assistant, no children appear under the GtkAssistant. Further I cannot select (or delete or change) the contents of the 3 default pages Glade produces -- I can only select the assistant itself.
So, I try increasing the number of pages to 5 and then adding a widget to one of the new pages. It gives me the error message: "Widgets of type Assistant need placeholders to add children."
Is this a bug, or am I missing something fundamental about how I'm supposed to configure an assistant window?
This question might be related; but it's very vague and has not been answered.
I am running Glade 3.12.1 on Ubuntu 12.04.
来源：https://stackoverflow.com/questions/12023809/glade-how-to-edit-pages-in-a-gtkassistant