GTK+ 3.18 Will Drop Support for Windows XP, Brings Horizontal Wheel Scrolling

Starting with GTK+ 3.17.1, support for Microsoft’s Windows XP operating system has been dropped. In addition, support for horizontal mouse wheel scrolling has been added for Microsoft Windows OSes. Also, attached modal dialogs with Mutter are now supported in Wayland, and over 60 bugs were fixed, including broken Firefox scrollbars.