Here is a quick tour of what you missed if you did not make it to my Guadec talk this year.
It was a bit different from my usual ‘state of the union’ or ‘GTK+ roadmap’ presentations. Instead, I showed a selection of tips and tricks, things you perhaps didn’t know yet how to do with GTK+.
Scrollbar steppers still exist
Context menus on scrollbars
Adding items to context menus and popovers
Custom spin buttons
Markup in text views
Filter models with extra columns
The slides are here, and if you want to study the examples in more detail, they are all available in gtk3-demo in GTK+ master.