Adds a region to context, so posterior calls to Style.contextGet or any of the gtk_render_*() functions will make use of this new region for styling.

In the CSS file format, a gtk.TreeView defining a “row” region, would be matched by:

|[ <!-- language="CSS" --> treeview row { ... }

Pseudo-classes are used for matching `flags`, so the two
following rules:
|[ <!-- language="CSS" -->
treeview row:nth-child(even) { ... }
treeview row:nth-child(odd) { ... }

would apply to even and odd rows, respectively.

Region names must only contain lowercase letters and “-”, starting always with a lowercase letter.

class StyleContext


regionName string

region name to use in styling

flags GtkRegionFlags

flags that apply to the region