title: Why gtk css widget styling does not work?
body: <p>I'm trying to style widget from inside of it's constructor in Vala but I don't get the result I want. Here is the original code sample:</p>
  
  <pre><code>public class MyWidget : Gtk.FlowBox {
  
      public MyWidget () {
          var css_provider = new Gtk.CssProvider ();
          try {
              css_provider.load_from_data (
                  """
                  label {
                      color: blue;
                  }
                  """
              );
              get_style_context ().add_provider (css_provider, Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION);
          } catch (Error e) {
              message ("error");
          }
      }
  
      public void add_entry (string s) {
          var entry = new Gtk.Label (s);
          add (entry);
      }
  
  }
  </code></pre>
  
  <p>I've tried all different variants of styling "flowbox", "flowboxchild", "label" etc. and only one that works is "*" for every element inside GtkFlowbox or assigning it to a class, thought I still can't style it's children. Priorities don't seem to change anything, adding global "flowbox" styles for screen context don't work too.</p>
  
  <p>I've tried to do it using gtk inspector but no result here too.</p>
  
  <p>So how do I style all children of widget? Or do I need to specify class for them?</p>