GTK+ GUI Toolkit Updated for GNOME 3.21.3 with More Wayland Improvements

GTK+ 3.21.3 updates widgets like GtkStack, bringing its own accessible implementation, as well as GtkScrolledWindow, which includes new max-content-width and max-content-height properties for controlling its size. Additionally, the GtkFileChooser widget has been updated to include support for Tracker’s FTS5 syntax, thus offering a much-improved search functionality, the styling of the GtkProgressBar and GtkScale widgets is now determined by the correct CSS nodes, and GdkInputSource’s enumeration has received a new environment variable to allow special-casing to input devices.