Gtk Button override_background_color not working on some themes

Question

I'm trying to override the background color of a gtk button with vala but it's not working on some themes. So, this code

var b = new Button ();
b.label = "test";
b.margin = 10;
b.override_background_color (Gtk.StateFlags.NORMAL, color (yellow));

look like this on:

Adapta (What I want)

Adwaita

Ambiance

So what am I missing there?

Answer 1

gtk_widget_override_background_color() is deprecated and no longer used. Use CSS instead:

var css = "* { background: #FFFF00; }";
var p = new Gtk.CssProvider();
try {
    p.load_from_data(css, css.length);
    b.get_style_context().add_provider(p, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
} catch (GLib.Error err) {
    // handle err
}