Add empty placeholder and use better style

data/interface.ui

 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-  SPDX-FileCopyrightText: 2012-2020 Bruce Cowan <bruce@bcowan.me.uk>
+  SPDX-FileCopyrightText: 2012-2021 Bruce Cowan <bruce@bcowan.me.uk>
   SPDX-License-Identifier: GPL-3.0-or-later
 -->
 <interface>
@@ -29,7 +29,7 @@
     <property name="title" translatable="yes">Rugby</property>
     <child>
       <object class="GtkScrolledWindow">
-        <property name="height_request">400</property>
+        <property name="height_request">600</property>
         <property name="child">
           <object class="GtkViewport">
             <property name="can_focus">0</property>
@@ -37,6 +37,17 @@
               <object class="GtkListBox" id="listbox">
                 <property name="can_focus">0</property>
                 <property name="selection_mode">none</property>
+                <style>
+                  <class name="rich-list"/>
+                </style>
+                <child type="placeholder">
+                  <object class="GtkLabel">
+                    <property name="label">No possibilities for this score</property>
+                    <style>
+                      <class name="dim-label"/>
+                    </style>
+                  </object>
+                </child>
               </object>
             </property>
           </object>

data/rugby.css

@@ -5,7 +5,7 @@
 
 .possibility.score-block
 {
-    border-radius: 10px;
+    border-radius: 15px;
 }
 
 .possibility.score-block.try

src/main.c

 /*
- * SPDX-FileCopyrightText: 2012-2020 Bruce Cowan <bruce@bcowan.me.uk>
+ * SPDX-FileCopyrightText: 2012-2021 Bruce Cowan <bruce@bcowan.me.uk>
  * SPDX-License-Identifier: GPL-3.0-or-later
  */
 
@@ -33,7 +33,7 @@ about_activated (G_GNUC_UNUSED GSimpleAction *simple,
     gtk_show_about_dialog (window,
                            "logo-icon-name", "face-wink",
                            "program-name", "Rugby",
-                           "copyright", "Copyright 2012–2020 Bruce Cowan",
+                           "copyright", "Copyright 2012–2021 Bruce Cowan",
                            "license-type", GTK_LICENSE_GPL_3_0,
                            "authors", authors,
                            "comments", "Rugby scores possiblities program",

src/rugby-possibility-widget.c

@@ -26,8 +26,6 @@ enum
 
 static GParamSpec *properties[N_PROPS];
 
-#define FIXED_HEIGHT 20
-
 static void
 rugby_possibility_widget_dispose (GObject *object)
 {
@@ -75,23 +73,6 @@ rugby_possibility_widget_set_property (GObject      *object,
     }
 }
 
-static void
-rugby_possibility_widget_measure (G_GNUC_UNUSED GtkWidget *widget,
-                                  GtkOrientation           orientation,
-                                  G_GNUC_UNUSED int        for_size,
-                                  int                     *minimum,
-                                  int                     *natural,
-                                  G_GNUC_UNUSED int       *minimum_baseline,
-                                  G_GNUC_UNUSED int       *natural_baseline)
-
-{
-    if (orientation == GTK_ORIENTATION_VERTICAL)
-    {
-        *minimum = FIXED_HEIGHT;
-        *natural = FIXED_HEIGHT;
-    }
-}
-
 static void
 render_bar (cairo_t         *cr,
             GtkStyleContext *context,
@@ -195,15 +176,12 @@ static void
 rugby_possibility_widget_class_init (RugbyPossibilityWidgetClass *klass)
 {
     GObjectClass *object_class = G_OBJECT_CLASS (klass);
-    GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
 
     object_class->constructed = rugby_possibility_widget_constructed;
     object_class->dispose = rugby_possibility_widget_dispose;
     object_class->get_property = rugby_possibility_widget_get_property;
     object_class->set_property = rugby_possibility_widget_set_property;
 
-    widget_class->measure = rugby_possibility_widget_measure;
-
     properties[PROP_POSSIBILITY] = g_param_spec_object ("possibility",
                                                         "Possibility",
                                                         "Possibility to be represented",